PMID-sentid Pub_year Sent_text comp_official_name comp_offsetprotein_name organism prot_offset 16445854-2 2006 Tyrosinase, the primary enzyme in melanin synthesis commonly mutated in albinism, oxidizes l-tyrosine to l-dopaquinone using l-3,4-dihydroxyphenylalanine (L-DOPA) as an intermediate product. Levodopa 125-153 tyrosinase Homo sapiens 0-10 18670186-3 2008 Glutathione inhibited the binding between tyrosinase and L-DOPA. Levodopa 57-63 tyrosinase Homo sapiens 42-52 18569714-4 2008 Tyrosinase is a key enzyme, which catalyzes the conversion of L-tyrosine to L-dihydroxyalanine (L-Dopa), therefore tyrosinase inhibitors are used in various skin preparations due to its pronounced effect on anti-hyperpigment. Levodopa 96-102 tyrosinase Homo sapiens 0-10 18569714-4 2008 Tyrosinase is a key enzyme, which catalyzes the conversion of L-tyrosine to L-dihydroxyalanine (L-Dopa), therefore tyrosinase inhibitors are used in various skin preparations due to its pronounced effect on anti-hyperpigment. Levodopa 96-102 tyrosinase Homo sapiens 115-125 18324837-3 2008 Oxidation of the capping layer by TR/O2 yields the respective L-DOPA and dopaquinone products. Levodopa 62-68 tyrosinase Homo sapiens 34-36 17131995-3 2006 The tyrosine units were reacted with tyrosinase/O2 to yield the respective l-DOPA and quinone derivatives. Levodopa 75-81 tyrosinase Homo sapiens 37-47 16919455-3 2006 A kinetic study revealed that 7 was a reversible and non-competitive inhibitor of mushroom tyrosinase with l-dopa as the substrate. Levodopa 107-113 tyrosinase Homo sapiens 91-101 16841367-3 2006 Tyrosinase catalyses three different reactions in the biosynthetic pathway of melanin in melanocytes: the hydroxylation of tyrosine to l-DOPA and the oxidation of l-DOPA to dopaquinone; furthermore, in humans, dopaquinone is converted by a series of complex reactions to melanin. Levodopa 135-141 tyrosinase Homo sapiens 0-10 16841367-3 2006 Tyrosinase catalyses three different reactions in the biosynthetic pathway of melanin in melanocytes: the hydroxylation of tyrosine to l-DOPA and the oxidation of l-DOPA to dopaquinone; furthermore, in humans, dopaquinone is converted by a series of complex reactions to melanin. Levodopa 163-169 tyrosinase Homo sapiens 0-10 18828673-10 2008 Further, inhibition of tyrosinase, the enzyme that makes L-DOPA, resulted in decreased PEDF secretion by RPE. Levodopa 57-63 tyrosinase Homo sapiens 23-33 18828673-12 2008 Taken together, our results illustrate an autocrine loop between OA1 and tyrosinase linked through L-DOPA, and this loop includes the secretion of at least one very potent retinal neurotrophic factor. Levodopa 99-105 tyrosinase Homo sapiens 73-83 18270468-3 2008 Inhibition kinetics studies revealed that imperanene is a competitive inhibitor of tyrosinase when L-3,4-dihydroxyphenylalanine is used as the substrate. Levodopa 99-127 tyrosinase Homo sapiens 83-93 16950829-9 2006 Identification of the enzymes as tyrosinases was confirmed by the ability of lichen thalli or leachates derived by shaking lichens in distilled water to metabolize substrates such as L-dihydroxyphenylalanine (DOPA), tyrosine and epinephrine readily in the absence of hydrogen peroxide, the sensitivity of the enzymes to the inhibitors cyanide, azide and hexylresorcinol, activation by SDS and having typical tyrosinase molecular masses of approx. Levodopa 183-207 tyrosinase Homo sapiens 33-43 16950829-9 2006 Identification of the enzymes as tyrosinases was confirmed by the ability of lichen thalli or leachates derived by shaking lichens in distilled water to metabolize substrates such as L-dihydroxyphenylalanine (DOPA), tyrosine and epinephrine readily in the absence of hydrogen peroxide, the sensitivity of the enzymes to the inhibitors cyanide, azide and hexylresorcinol, activation by SDS and having typical tyrosinase molecular masses of approx. Levodopa 209-213 tyrosinase Homo sapiens 33-43 16445854-2 2006 Tyrosinase, the primary enzyme in melanin synthesis commonly mutated in albinism, oxidizes l-tyrosine to l-dopaquinone using l-3,4-dihydroxyphenylalanine (L-DOPA) as an intermediate product. Levodopa 155-161 tyrosinase Homo sapiens 0-10 15214892-7 2004 Cell cycles were determined by flow cytometry, and the activity of tyrosinase was evaluated by L-DOPA reaction. Levodopa 95-101 tyrosinase Homo sapiens 67-77 16293777-9 2005 Furthermore, we show intra-melanosomal l-dopa formation from dopachrome by 7BH(4) in a concentration range up to 134 x 10(-6) M. Based on these results, we propose a new receptor-independent mechanism in the control of tyrosinase/melanogenesis by beta-MSH and the pterin 7BH(4). Levodopa 39-45 tyrosinase Homo sapiens 219-229 15778083-1 2005 The tyrosinase/oxygen enzymatic system catalyses the orthohydroxylation of L-tyrosine to L-dopa and the oxidation of this to dopaquinone, which evolves non-enzymatically towards to form melanins. Levodopa 89-95 tyrosinase Homo sapiens 4-14 21706729-1 2004 Tyrosinase (EC 1.14.18.1) catalyzes the oxidation of L-3,4-dihydroxyphenylalanine (L-DOPA) to 2,3,5,6-tetrahydro-5,6-dioxo-1H-indole-2-carboxylate (dopachrome), according to the classical Michaelis-Menten kinetic mechanism. Levodopa 53-81 tyrosinase Homo sapiens 0-10 21706729-1 2004 Tyrosinase (EC 1.14.18.1) catalyzes the oxidation of L-3,4-dihydroxyphenylalanine (L-DOPA) to 2,3,5,6-tetrahydro-5,6-dioxo-1H-indole-2-carboxylate (dopachrome), according to the classical Michaelis-Menten kinetic mechanism. Levodopa 83-89 tyrosinase Homo sapiens 0-10 16392817-3 2006 Several aurones bearing hydroxyl groups on A-ring and different substituents on B-ring were synthesized and evaluated as inhibitors of human melanocyte-tyrosinase by an assay which measures tyrosinase-catalyzed l-Dopa oxidation. Levodopa 211-217 tyrosinase Homo sapiens 190-200 16280010-6 2005 Kinetic data suggest that all four compounds act as competitive inhibitors of tyrosinase, most likely competing with L-3,4-dihydroxyphenylalanine (L-DOPA) for binding to the DOPA-binding site of the enzyme. Levodopa 117-145 tyrosinase Homo sapiens 78-88 16280010-6 2005 Kinetic data suggest that all four compounds act as competitive inhibitors of tyrosinase, most likely competing with L-3,4-dihydroxyphenylalanine (L-DOPA) for binding to the DOPA-binding site of the enzyme. Levodopa 147-153 tyrosinase Homo sapiens 78-88 14646622-2 2003 We have already shown that the serum L-dopa/L-tyrosine ratio (an index of tyrosinase functional activity) correlates with the tumour burden and in some cases predicted disease progression in metastatic melanoma patients. Levodopa 37-43 tyrosinase Homo sapiens 74-84 15003008-4 2004 On the other hand, the polycondensates inhibited the tyrosine hydroxylation and L-DOPA oxidation by chelation to the active site of tyrosinase. Levodopa 80-86 tyrosinase Homo sapiens 132-142 12069421-1 2002 Hydroxylation of peptidyl-3,4-dihydroxyphenyl-l-alanine (Dopa) was observed during tyrosinase incubation of a decapeptide related to the mussel adhesive protein mefp1. Levodopa 57-61 tyrosinase Homo sapiens 83-93 14577637-2 2003 It inhibited the oxidation of L-3,4-dihydroxyphenylalanine (L-DOPA) catalyzed by tyrosinase with an IC50 of 0.60 mM. Levodopa 30-58 tyrosinase Homo sapiens 81-91 14577637-2 2003 It inhibited the oxidation of L-3,4-dihydroxyphenylalanine (L-DOPA) catalyzed by tyrosinase with an IC50 of 0.60 mM. Levodopa 60-66 tyrosinase Homo sapiens 81-91 12631248-7 2003 The melanosomal membrane location of tyrosine hydroxylase together with tyrosinase implies a coupled interaction, where L-dopa production facilitates the activation of tyrosinase. Levodopa 120-126 tyrosinase Homo sapiens 72-82 12631248-7 2003 The melanosomal membrane location of tyrosine hydroxylase together with tyrosinase implies a coupled interaction, where L-dopa production facilitates the activation of tyrosinase. Levodopa 120-126 tyrosinase Homo sapiens 168-178 12835121-7 2003 The melanin-synthetic enzyme tyrosinase in the brain may rapidly oxidize excess amounts of cytosolic DA and L-DOPA, thereby preventing slowly progressive cell damage by auto-oxidation of DA, thus maintainng DA levels. Levodopa 108-114 tyrosinase Homo sapiens 29-39 12835121-8 2003 Since tyrosinase also possesses catecholamine-synthesizing activity in the absence of tyrosine hydroxylase (TH), the double-edged synthesizing and oxidizing functions of tyrosinase in the dopaminergic system suggest its potential for application in the synthesis of DA, instead of TH in the degeneration of dopaminergic neurons, and in the normalization of abnormal DA turnover in the long-term L-DOPA-treated Parkinson"s disease patients. Levodopa 395-401 tyrosinase Homo sapiens 6-16 12835121-8 2003 Since tyrosinase also possesses catecholamine-synthesizing activity in the absence of tyrosine hydroxylase (TH), the double-edged synthesizing and oxidizing functions of tyrosinase in the dopaminergic system suggest its potential for application in the synthesis of DA, instead of TH in the degeneration of dopaminergic neurons, and in the normalization of abnormal DA turnover in the long-term L-DOPA-treated Parkinson"s disease patients. Levodopa 395-401 tyrosinase Homo sapiens 170-180 12622939-2 2002 METHODS: Tyrosinase activity was estimated by measuring the oxidation rate of L-dopa. Levodopa 78-84 tyrosinase Homo sapiens 9-19 12235154-2 2002 Whereas 3- and 4-fluorophenol react with tyrosinase to give products that undergo a rapid polymerization process, 2-fluorophenol is not reactive and actually acts as a competitive inhibitor in the enzymatic oxidation of 3,4-dihydroxyphenylalanine (L-dopa). Levodopa 248-254 tyrosinase Homo sapiens 41-51 12760744-4 2003 The half-life of the GE enzyme at 40 degrees C was less than 2 h, whereas the FEAGE enzyme retained about 75% of its initial activity after 2 h. Taken together our data demonstrate clearly that the technique of immobilizing tyrosinase via adsorption followed by entrapment appears promising and is hence recommended for tyrosinase immobilization for commercial production of L-DOPA (3,4-dihydroxyphenylalanine). Levodopa 375-381 tyrosinase Homo sapiens 224-234 12802729-2 2003 Mushroom tyrosinase activity was inhibited in a concentration-dependent manner when treated with kinobeon A using L-tyrosine or L-3,4-dihydroxyphenylalannine (L-DOPA) as substrates. Levodopa 159-165 tyrosinase Homo sapiens 9-19 12802729-4 2003 Inhibition of human tyrosinase activity also increased with increasing concentrations of kinobeon A using L-DOPA as the substrate, with an IC50 value of 2.5 microM. Levodopa 106-112 tyrosinase Homo sapiens 20-30 12624268-6 2003 These experiments raise the possibility that a tyrosinase/l-dopa pathway modifies human PCG, which could open new therapeutic avenues. Levodopa 58-64 tyrosinase Homo sapiens 47-57 11781109-10 2002 However, replacement of Q (in Tyr) by H (in Tyrps) greatly diminished the affinity for L-dopa, consistent with the low/null tyrosinase activity of the Tyrps. Levodopa 87-93 tyrosinase Homo sapiens 30-33 11781109-10 2002 However, replacement of Q (in Tyr) by H (in Tyrps) greatly diminished the affinity for L-dopa, consistent with the low/null tyrosinase activity of the Tyrps. Levodopa 87-93 tyrosinase Homo sapiens 124-134 11312883-6 2001 Tyrosinase was purified in a homogeneous form by SDS-PAGE and was characterized: its specific activity toward 3-(3,4-dihydroxyphenyl)-L-alanine (DOPA) increased by a factor of 24 with an overall recovery of 3% of initial activity. Levodopa 110-143 tyrosinase Homo sapiens 0-10 11425590-1 2001 Several benzaldoximes, benzaldehyde-O-ethyloximes, and acetophenonoximes were synthesized and evaluated as tyrosinase inhibitors by an assay based on tyrosinase catalyzed L-DOPA oxidation. Levodopa 171-177 tyrosinase Homo sapiens 107-117 11425590-1 2001 Several benzaldoximes, benzaldehyde-O-ethyloximes, and acetophenonoximes were synthesized and evaluated as tyrosinase inhibitors by an assay based on tyrosinase catalyzed L-DOPA oxidation. Levodopa 171-177 tyrosinase Homo sapiens 150-160 11258976-3 2001 L-DOPA, a precursor of eumelanin, was oxidized and oligomerized with tyrosinase. Levodopa 0-6 tyrosinase Homo sapiens 69-79 11312883-6 2001 Tyrosinase was purified in a homogeneous form by SDS-PAGE and was characterized: its specific activity toward 3-(3,4-dihydroxyphenyl)-L-alanine (DOPA) increased by a factor of 24 with an overall recovery of 3% of initial activity. Levodopa 145-149 tyrosinase Homo sapiens 0-10 7826365-5 1995 When L-dopa is substrate, 6-BH4 does not inhibit the enzyme implicating separate binding sites for L-dopa and L-tyrosine on tyrosinase. Levodopa 99-105 tyrosinase Homo sapiens 124-134 9242453-7 1997 In addition, we used the 3,4-dihydroxy-L-phenylalanine reaction to detect tyrosinase enzyme activity as a confirmation of the tyrosinase immunohistochemical results in a subset of the lesions. Levodopa 25-54 tyrosinase Homo sapiens 74-84 9479530-3 1996 To date, only the hair-bulb L-dopa incubation test has been helpful in discriminating between the tyrosinase (ty)-negative and ty-positive forms of OCA. Levodopa 28-34 tyrosinase Homo sapiens 98-108 8632348-7 1996 The utilization of L-tyrosine or L-dopa as the substrate suggests a mechanism involving competition with arbutin for the L-tyrosine binding site at the active site of tyrosinase. Levodopa 33-39 tyrosinase Homo sapiens 167-177 8578949-5 1995 Whereas the oxidation of L-dopa catalysed by tyrosinase ws inhibited by L-tyrosine, the non-specific oxidation of D-dopa was not. Levodopa 25-31 tyrosinase Homo sapiens 45-55 11171088-2 2001 Tyrosinase catalyses the rate-limiting generation of L-dopaquinone from L-tyrosine and is also able to oxidize L-dopa to L-dopaquinone. Levodopa 53-59 tyrosinase Homo sapiens 0-10 10849837-0 2000 L-DOPA production by immobilized tyrosinase. Levodopa 0-6 tyrosinase Homo sapiens 33-43 10849837-1 2000 The production of L-DOPA using L-tyrosine as substrate, the enzyme tyrosinase (EC 1.14.18.1) as biocatalyst, and L-ascorbate as reducing agent for the o-quinones produced by the enzymatic oxidation of the substrates was studied. Levodopa 18-24 tyrosinase Homo sapiens 67-77 18624322-0 1996 L-DOPA production from tyrosinase immobilized on nylon 6,6. Levodopa 0-6 tyrosinase Homo sapiens 23-33 7556145-7 1995 Upon incubation of a melanosome-rich fraction with the melanin precursor L-3,4-dihydroxyphenylalanine (Dopa) followed by immunoblot analysis, the si locus protein, the p locus protein, and other putative matrix constituents became rapidly insoluble in SDS when compared with the members of the tyrosinase-related family of melanosomal membrane proteins. Levodopa 73-101 tyrosinase Homo sapiens 294-304 7937580-6 1994 Fetal skin samples incubated with L-DOPA solution indicated a lack of tyrosinase activity and showed that the melanosomes had not progressed beyond stage II. Levodopa 34-40 tyrosinase Homo sapiens 70-80 8064113-2 1994 The assay measures the pink pigment formed by the reaction of Besthorn"s hydrazone (3-methyl-2-benzothiazoninone hydrazone, or MBTH) with dopaquinone, the product of oxidation of L-dopa by tyrosinase. Levodopa 179-185 tyrosinase Homo sapiens 189-199 8207328-1 1994 In melanocytes, the biosynthesis of L-dopa derived indole polymer, melanin, is accelerated by tyrosinase and related enzymes. Levodopa 36-42 tyrosinase Homo sapiens 94-104 1429711-1 1992 Tyrosinase (EC 1.14.18.1) is a copper-containing metalloglycoprotein that catalyzes several steps in the melanin pigment biosynthetic pathway; the hydroxylation of tyrosine to L-3,4-dihydroxyphenylalanine (dopa) and the subsequent oxidation of dopa to dopaquinone. Levodopa 176-204 tyrosinase Homo sapiens 0-10 8123719-1 1993 An enzyme-amperometric method is proposed for the analysis of total phenols and L-dopa; the method is based on the enzyme tyrosinase, which is immobilized in a Nylon membrane and coupled to an oxygen gas-diffusion amperometric electrode. Levodopa 80-86 tyrosinase Homo sapiens 122-132 8507669-6 1993 On the basis of these results, it is proposed that the influence of ferrous ions on tyrosinase is due to the formation of dopa in the chemical hydroxylation of tyrosine. Levodopa 122-126 tyrosinase Homo sapiens 84-94 7901010-8 1993 The tyrosinase activity of control and theophylline-treated extracts displayed several kinetic differences, including different Km values for both substrates and requirements for the cofactor L-dopa. Levodopa 192-198 tyrosinase Homo sapiens 4-14 8270948-2 1993 After incubation with 5 mM L-DOPA for several hours the endogenous tyrosinase of the haemolymph forms an electron dense reaction product. Levodopa 27-33 tyrosinase Homo sapiens 67-77 1429711-1 1992 Tyrosinase (EC 1.14.18.1) is a copper-containing metalloglycoprotein that catalyzes several steps in the melanin pigment biosynthetic pathway; the hydroxylation of tyrosine to L-3,4-dihydroxyphenylalanine (dopa) and the subsequent oxidation of dopa to dopaquinone. Levodopa 206-210 tyrosinase Homo sapiens 0-10 1429711-1 1992 Tyrosinase (EC 1.14.18.1) is a copper-containing metalloglycoprotein that catalyzes several steps in the melanin pigment biosynthetic pathway; the hydroxylation of tyrosine to L-3,4-dihydroxyphenylalanine (dopa) and the subsequent oxidation of dopa to dopaquinone. Levodopa 244-248 tyrosinase Homo sapiens 0-10 1906272-1 1991 Melanin biosynthesis is a multistep process with the first step being the conversion of L-tyrosine to L-Dopa catalyzed by the enzyme tyrosinase. Levodopa 102-108 tyrosinase Homo sapiens 133-143 1653610-8 1991 Bis-cysteinate tyrosinase activity is down-regulated to 30% of native enzyme activity in the L-dopa assay; suggesting a true regulatory role for dithiols. Levodopa 93-99 tyrosinase Homo sapiens 15-25 1388592-1 1992 The influence of bioisosteric replacement of catechol moiety of L-Dopa and alpha-Methyldopa with benzimidazole and benzotriazole ring has been examined on dopamine beta-hydroxylase and tyrosinase, in order to evidentiate an inhibitory activity on the synthesis of catecholamines and a possible antihypertensive action. Levodopa 64-70 tyrosinase Homo sapiens 185-195 1653780-5 1991 The growth of neuroblastoma tumours was inhibited by different mechanisms: L-dopa and its metabolite dopamine reduced the activity of tyrosinase, BSO reduced glutathione levels, and L-dopa and tamoxifen raised cAMP concentrations. Levodopa 75-81 tyrosinase Homo sapiens 134-144 1900435-2 1991 Tyrosinase catalyzes the oxidation by molecular oxygen of L-dopa to o-dopaquinone, which evolves non-enzymatically through a branched pathway with cyclization or hydroxylation reactions. Levodopa 58-64 tyrosinase Homo sapiens 0-10 34882402-2 2022 Herein, we identified S05014 (l-Tyr, IC50 = 6.25 +- 1.43 nM; l-Dopa, IC50 = 0.64 +- 0.40 muM) as a highly effective tyrosinase inhibitor. Levodopa 61-67 tyrosinase Homo sapiens 116-126 34073856-4 2021 This paper provides a proof-of-concept method for enzymatically creating levodopa-containing proteins using the enzyme tyrosinase and provides spectral evidence of in vitro incorporation in addition to the induction of the unfolded protein response due to levodopa. Levodopa 73-81 tyrosinase Homo sapiens 119-129 34498463-1 2021 In living organisms, tyrosinase selectively produces l-DOPA from l-tyrosine. Levodopa 53-59 tyrosinase Homo sapiens 21-31 34498463-2 2021 Here, a bicomponent hydrogel is used as a template for tyrosinase-catalyzed selective generation of l-DOPA from tyrosine. Levodopa 100-106 tyrosinase Homo sapiens 55-65 34140181-1 2021 A series of aryl phenoxy methyl triazole conjugated with thiosemicarbazides were designed, synthesized, and evaluated for their tyrosinase inhibitory activities in the presence of l-dopa and l-tyrosine as substrates. Levodopa 180-186 tyrosinase Homo sapiens 128-138 34140181-3 2021 Among the derivatives, compound 9j bearing benzyl displayed exceptionally high potency against tyrosinase with IC50 value of 0.11 muM and 0.17 muM in the presence of l-tyrosine and l-dopa as substrates which is significantly lower than that of kojic acid as the positive control with an IC50 value of 9.28 muM for l-tyrosine and 9.30 muM for l-dopa. Levodopa 181-187 tyrosinase Homo sapiens 95-105 34140181-3 2021 Among the derivatives, compound 9j bearing benzyl displayed exceptionally high potency against tyrosinase with IC50 value of 0.11 muM and 0.17 muM in the presence of l-tyrosine and l-dopa as substrates which is significantly lower than that of kojic acid as the positive control with an IC50 value of 9.28 muM for l-tyrosine and 9.30 muM for l-dopa. Levodopa 342-348 tyrosinase Homo sapiens 95-105 34757293-4 2021 The congener proteins treated with tyrosinase convert 3, 4-dihydroxy-l-phenylalanine to dopaquinone for strain-promoted click chemistry. Levodopa 54-84 tyrosinase Homo sapiens 35-45 35500310-0 2022 A selective dual-response biosensor for tyrosinase monophenolase activity based on lanthanide metal-organic frameworks assisted boric acid-levodopa polymer dots. Levodopa 139-147 tyrosinase Homo sapiens 40-50 3572026-4 1987 The mechanism of action may involve interaction with the melanocyte-specific enzyme, tyrosinase, for which the cysteinylcatechols could become a better substrate than L-dopa itself. Levodopa 167-173 tyrosinase Homo sapiens 85-95 35185418-3 2022 NaOH method was used for melanin content assay, cellular tyrosinase (TYR) activity was determined by 3,4-Dihydroxy-L-phenylalanine (L-DOPA) oxidation to dopachrome, premature senescence was analyzed by senescence-associated beta-galactosidase (SA-beta-gal) staining kit, and the levels of p21, p16, p62, and GATA4 proteins were detected by Western blotting. Levodopa 132-138 tyrosinase Homo sapiens 57-67 3125836-7 1987 These results show that the effect of polyamines on mammalian tyrosinase is due to direct enzyme-oligoamine interactions rather than to a nonspecific action on L-dopa oxidation products, and suggest that physiological polyamines might play a modulatory role on mammalian melanogenesis. Levodopa 160-166 tyrosinase Homo sapiens 62-72 3120620-3 1987 5-S-Glutathione-L-dopa is first synthesized by the tyrosinase-catalyzed reaction between L-dopa and glutathione. Levodopa 16-22 tyrosinase Homo sapiens 51-61 35185418-3 2022 NaOH method was used for melanin content assay, cellular tyrosinase (TYR) activity was determined by 3,4-Dihydroxy-L-phenylalanine (L-DOPA) oxidation to dopachrome, premature senescence was analyzed by senescence-associated beta-galactosidase (SA-beta-gal) staining kit, and the levels of p21, p16, p62, and GATA4 proteins were detected by Western blotting. Levodopa 132-138 tyrosinase Homo sapiens 69-72 2907130-1 1988 This work describes a comparative study of the tyrosinase activity determined using three methods which are the most extensively employed; two radiometric assays using L-tyrosine as substrate (tyrosine hydroxylase and melanin formation activities) and one spectrophotometric assay using L-dopa (dopa oxidase activity). Levodopa 287-293 tyrosinase Homo sapiens 47-57 2907130-4 1988 The results show that mammalian tyrosinase has a greater turnover number for L-dopa than for L-tyrosine. Levodopa 77-83 tyrosinase Homo sapiens 32-42 93948-0 1979 Modulation of tyrosinase activity and viral information by 5-iodo-deoxyuridine and L-dopa in a human melanoma cell line [proceedings]. Levodopa 83-89 tyrosinase Homo sapiens 14-24 3927772-0 1985 A spectrophotometric assay for mammalian tyrosinase utilizing the formation of melanochrome from L-dopa. Levodopa 97-103 tyrosinase Homo sapiens 41-51 6441736-2 1984 The enzyme activity was detected by staining the gels with L-3,4-dihydroxyphenylalanine, dopamine and 5,6-dihydroxyindole as substrates for tyrosinase (EC 1.14.18.1). Levodopa 59-87 tyrosinase Homo sapiens 140-150 6407880-2 1983 The rate of tyrosinase formation has been calculated by coupling the activatory process of frog epidermis pro-tyrosinase by trypsin to the oxidation of L-DOPA to dopachrome. Levodopa 152-158 tyrosinase Homo sapiens 12-22 2431571-4 1986 This stereospecific dopa-oxidation is indicative of the presence of tyrosinase and corresponds well with earlier determinations of the rates of oxidation for human tyrosinase, using L-dopa and D-dopa as substrates. Levodopa 182-188 tyrosinase Homo sapiens 68-78 2431571-4 1986 This stereospecific dopa-oxidation is indicative of the presence of tyrosinase and corresponds well with earlier determinations of the rates of oxidation for human tyrosinase, using L-dopa and D-dopa as substrates. Levodopa 182-188 tyrosinase Homo sapiens 164-174 18551654-1 1984 Frog epidermis tyrosinase has been immobilized on Enzacryl-AA (a polyacrylamide-based support) and CPG(zirclad)-Arylamine (a controlled pore glass support) in order to stabilize the tyrosine hydroxylase activity of the enzyme; in this way, the immobilized enzyme could be used to synthesize L-dopa from L-tyrosine. Levodopa 291-297 tyrosinase Homo sapiens 15-25 18551654-3 1984 The results showed a noticeable improvement (in immobilization yield, coupling efficiency, and storage and operational stabilities) over previous reports in which tyrosinase was immobilized for L-dopa production. Levodopa 194-200 tyrosinase Homo sapiens 163-173 6799584-1 1982 Tyrosinase activity (Monophenol, dihydroxyphenylalanine: oxygen oxidoreductase EC 1.14.18.1) in vitiligo and normal epidermal homogenates of skin from human beings was measured by estimating beta 3,4-dihydroxyphenylalanine (dopa) by a highly sensitive fluorometric method described in this paper. Levodopa 191-222 tyrosinase Homo sapiens 0-10 6799584-3 1982 The activity of tyrosinase in normal human skin from different individuals and from different regions of the body was in the range of 4 to 140 picomoles of beta 3,4-dihydroxyphenylalanine formed per min/mg protein of epidermal homogenate. Levodopa 156-187 tyrosinase Homo sapiens 16-26 6173137-0 1981 Inhibition of reverse transcriptase by tyrosinase generated quinones related to levodopa and dopamine. Levodopa 80-88 tyrosinase Homo sapiens 39-49 6792292-4 1981 With this technique, tyrosinase from normally pigmented brown, black, blond, and red hairbulbs gives a single band when the gel is stained with L-dopa for enzyme activity. Levodopa 144-150 tyrosinase Homo sapiens 21-31 113092-3 1979 The electrophoretic patterns of serum tyrosinase, resolved by electrophoresis of a serum tyrosinase fraction followed by incubation of the gel sample with L-dopa, and represented as sets of RF"s of melanin bands, were characteristically different in melanoma, breast carcinoma, and certain other diseases. Levodopa 155-161 tyrosinase Homo sapiens 38-48 32464200-5 2020 Circular dichroism and molecular docking suggested that anthraquinones could not chelate directly the copper ions but they could bind to amino acid residues in the active site of tyrosinase via electrostatic forces and hydrophobic interactions, as well as hydrogen bonds, and the binding processes resulted in the conformational changes of tyrosinase and prevented the substrate (L-DOPA) from entering the active site, which led to the decrease of tyrosinase activity. Levodopa 380-386 tyrosinase Homo sapiens 179-189 16746558-0 1937 A comparative study of the production of l-3:4-dihydroxyphenylalanine from tyrosine by tyrosinase from various sources. Levodopa 41-69 tyrosinase Homo sapiens 87-97 33517217-1 2021 Tyrosinase is the key enzyme for melanogenesis with both monophenolase activity and diphenolase activity, which catalyzes the hydroxylation of tyrosine to L-DOPA and the further oxidation of DOPA, respectively. Levodopa 155-161 tyrosinase Homo sapiens 0-10 32781320-4 2020 The difference between the two strip signals with or without the tyrosinase extracted the levodopa signal from the samples. Levodopa 90-98 tyrosinase Homo sapiens 65-75 822750-0 1976 A sensitive new assay for the oxidation of 3,4-dihydroxy L-phenylalanine by tyrosinase. Levodopa 43-72 tyrosinase Homo sapiens 76-86 33450959-2 2021 Tyr catalyzes the oxidation of the substrate L-DOPA into dopachrome and melanin. Levodopa 45-51 tyrosinase Homo sapiens 0-3 33308130-3 2021 Melanin synthesis starts via the hydroxylation of L-tyrosine to L-3,4-dihydroxyphenylalanine (DOPA) catalyzed by the enzyme known as tyrosinase (TYR), which triggers further conversion reaction to DOPAquinone and then to DOPAchrome. Levodopa 64-92 tyrosinase Homo sapiens 133-143 33308130-3 2021 Melanin synthesis starts via the hydroxylation of L-tyrosine to L-3,4-dihydroxyphenylalanine (DOPA) catalyzed by the enzyme known as tyrosinase (TYR), which triggers further conversion reaction to DOPAquinone and then to DOPAchrome. Levodopa 64-92 tyrosinase Homo sapiens 145-148 33308130-3 2021 Melanin synthesis starts via the hydroxylation of L-tyrosine to L-3,4-dihydroxyphenylalanine (DOPA) catalyzed by the enzyme known as tyrosinase (TYR), which triggers further conversion reaction to DOPAquinone and then to DOPAchrome. Levodopa 94-98 tyrosinase Homo sapiens 133-143 33308130-3 2021 Melanin synthesis starts via the hydroxylation of L-tyrosine to L-3,4-dihydroxyphenylalanine (DOPA) catalyzed by the enzyme known as tyrosinase (TYR), which triggers further conversion reaction to DOPAquinone and then to DOPAchrome. Levodopa 94-98 tyrosinase Homo sapiens 145-148 32776353-4 2021 The action of tyrosinase on the enantiomers of tyrosine (L-tyrosine and D-tyrosine) and dopa (L-dopa and D-dopa) were studied for the first time focusing on quantitative transient phase kinetics. Levodopa 94-100 tyrosinase Homo sapiens 14-24 32640730-1 2020 Tyrosinase (TYR) is a metalloenzyme classified as a type-3 copper protein, which is involved in the synthesis of melanin through a catalytic process beginning with the conversion of the amino acid l-Tyrosine (l-Tyr) to l-3,4-dihydroxyphenylalanine (l-DOPA). Levodopa 219-247 tyrosinase Homo sapiens 0-10 32640730-1 2020 Tyrosinase (TYR) is a metalloenzyme classified as a type-3 copper protein, which is involved in the synthesis of melanin through a catalytic process beginning with the conversion of the amino acid l-Tyrosine (l-Tyr) to l-3,4-dihydroxyphenylalanine (l-DOPA). Levodopa 219-247 tyrosinase Homo sapiens 12-15 32640730-1 2020 Tyrosinase (TYR) is a metalloenzyme classified as a type-3 copper protein, which is involved in the synthesis of melanin through a catalytic process beginning with the conversion of the amino acid l-Tyrosine (l-Tyr) to l-3,4-dihydroxyphenylalanine (l-DOPA). Levodopa 219-247 tyrosinase Homo sapiens 0-3 32640730-1 2020 Tyrosinase (TYR) is a metalloenzyme classified as a type-3 copper protein, which is involved in the synthesis of melanin through a catalytic process beginning with the conversion of the amino acid l-Tyrosine (l-Tyr) to l-3,4-dihydroxyphenylalanine (l-DOPA). Levodopa 249-255 tyrosinase Homo sapiens 0-10 32640730-1 2020 Tyrosinase (TYR) is a metalloenzyme classified as a type-3 copper protein, which is involved in the synthesis of melanin through a catalytic process beginning with the conversion of the amino acid l-Tyrosine (l-Tyr) to l-3,4-dihydroxyphenylalanine (l-DOPA). Levodopa 249-255 tyrosinase Homo sapiens 12-15 32640730-1 2020 Tyrosinase (TYR) is a metalloenzyme classified as a type-3 copper protein, which is involved in the synthesis of melanin through a catalytic process beginning with the conversion of the amino acid l-Tyrosine (l-Tyr) to l-3,4-dihydroxyphenylalanine (l-DOPA). Levodopa 249-255 tyrosinase Homo sapiens 0-3 32204589-0 2020 Continuous Fluorometric Method for Determining the Monophenolase Activity of Tyrosinase on L-Tyrosine, through Quenching L-DOPA Fluorescence by Borate. Levodopa 121-127 tyrosinase Homo sapiens 77-87 32490491-5 2020 Molecular docking results showed that hydrophobic and hydrogen bonding forces played a dominant role in the binding of ECG to tyrosinase, affecting the binding affinity of l-dopa to tyrosinase, leading to a decrease in tyrosinase activity. Levodopa 172-178 tyrosinase Homo sapiens 126-136 32490491-5 2020 Molecular docking results showed that hydrophobic and hydrogen bonding forces played a dominant role in the binding of ECG to tyrosinase, affecting the binding affinity of l-dopa to tyrosinase, leading to a decrease in tyrosinase activity. Levodopa 172-178 tyrosinase Homo sapiens 182-192 32490491-5 2020 Molecular docking results showed that hydrophobic and hydrogen bonding forces played a dominant role in the binding of ECG to tyrosinase, affecting the binding affinity of l-dopa to tyrosinase, leading to a decrease in tyrosinase activity. Levodopa 172-178 tyrosinase Homo sapiens 182-192 31952126-5 2020 Using l-tyrosine and l-dopa as substrates, the effects of puerarin on the monophenolase and diphenolase activity of tyrosinase activity were investigated by the enzyme kinetics method. Levodopa 21-27 tyrosinase Homo sapiens 116-126 31872821-1 2020 Tyrosinase is a key enzyme that has long been considered as a biomarker for melanoma as it catalyzes the oxidation of tyrosine and l-DOPA in melanogenesis. Levodopa 131-137 tyrosinase Homo sapiens 0-10 32019134-5 2020 Michaelis-Menten constants were measured spectrophotometrically from diphenol oxidase reactions of Tyr, using L-3,4-dihydroxyphenylalanine (L-DOPA) as a substrate, at temperatures: 25, 31, 37, and 43 C. Under the same conditions, the Tyr structure and the L-DOPA binding activity were simulated using 3 ns molecular dynamics and docking. Levodopa 110-138 tyrosinase Homo sapiens 99-102 32019134-5 2020 Michaelis-Menten constants were measured spectrophotometrically from diphenol oxidase reactions of Tyr, using L-3,4-dihydroxyphenylalanine (L-DOPA) as a substrate, at temperatures: 25, 31, 37, and 43 C. Under the same conditions, the Tyr structure and the L-DOPA binding activity were simulated using 3 ns molecular dynamics and docking. Levodopa 140-146 tyrosinase Homo sapiens 99-102 32019134-5 2020 Michaelis-Menten constants were measured spectrophotometrically from diphenol oxidase reactions of Tyr, using L-3,4-dihydroxyphenylalanine (L-DOPA) as a substrate, at temperatures: 25, 31, 37, and 43 C. Under the same conditions, the Tyr structure and the L-DOPA binding activity were simulated using 3 ns molecular dynamics and docking. Levodopa 257-263 tyrosinase Homo sapiens 99-102 32019134-7 2020 The temperature-dependent analysis suggests that the association of L-DOPA with Tyr is a spontaneous enthalpy-driven reaction, which becomes unfavorable at the final step of dopachrome formation. Levodopa 68-74 tyrosinase Homo sapiens 80-83 30326223-2 2019 In this study, we evaluated the dual effect of pyrogallol on tyrosinase as an inhibitor in the presence of L-DOPA simultaneously via integrating methods of enzyme kinetics and computational molecular dynamics (MD) simulations. Levodopa 107-113 tyrosinase Homo sapiens 61-71 31279520-4 2019 Based on the broad substrate spectrum, tyrosinase has been used in bioremediation of phenolic pollutants, constructing biosensors for identifying phenolic compounds, and L-DOPA synthesis. Levodopa 170-176 tyrosinase Homo sapiens 39-49 31279520-6 2019 Accordingly, tyrosinase might be a potential biocatalyst for industrial applications (e.g., electroenzymatic L-DOPA production, but its long-term stability and reusability should be further explored. Levodopa 109-115 tyrosinase Homo sapiens 13-23 31279520-7 2019 In this review, we emphasize the versatility of tyrosinase, which includes conventional applications, and suggest new perspectives as an industrial biocatalyst (e.g., electroenzymatic L-DOPA production). Levodopa 184-190 tyrosinase Homo sapiens 48-58 30907884-8 2019 In melanogenesis, tyrosinase catalyzes the rate-limiting step that converts L-tyrosine into 3,4-dihydroxyphenylalanine (L-DOPA) and then into dopaquinone. Levodopa 120-126 tyrosinase Homo sapiens 18-28 30907884-10 2019 In cultured melanocytes, tyrosinase activity can be quantified by adding L-DOPA as a substrate and measuring dopaquinone production by spectrophotometry. Levodopa 73-79 tyrosinase Homo sapiens 25-35 30326223-3 2019 Pyrogallol was found to be a reversible inhibitor of tyrosinase in the presence of L-DOPA and its induced mechanism was the parabolic non-competitive inhibition type (IC50 = 0.772 +- 0.003 mM and Ki = 0.529 +- 0.022 mM). Levodopa 83-89 tyrosinase Homo sapiens 53-63 29383286-7 2018 It dose-dependently inhibited the activity of tyrosinase, with the IC50 values 6.2 +- 2.0 microM and 10.3 +- 5.4 microM on tyrosine and L-Dopa formation, respectively. Levodopa 136-142 tyrosinase Homo sapiens 46-56 30063931-1 2018 The kinetic action of tyrosinase on l-tyrosine and l-Dopa as substrates in the presence of cinnamic acid and some of its derivatives has been characterized. Levodopa 51-57 tyrosinase Homo sapiens 22-32 29479807-4 2018 7,8,4 -Trihydroxyflavone was found to strongly inhibit the oxidation of l-DOPA by tyrosinase with an IC50 value of 10.31 +- 0.41 muM. Levodopa 72-78 tyrosinase Homo sapiens 82-92 29447969-4 2018 In accordance with the kinetic profile, molecular docking results show that PMI-5 is able to interact favorably with the tyrosinase active site containing the substrate molecule, L-DOPA, interacting with Val-247, Phe-263 and Val-282 residues. Levodopa 179-185 tyrosinase Homo sapiens 121-131 27840215-3 2017 Spectrophotometric analysis used to determine the inhibition capabilities of these compounds on tyrosinase catalyzing L-tyrosine (L-Tyr) and L-3,4-Dihydroxyphenylalanine (L-DOPA) as well. Levodopa 141-169 tyrosinase Homo sapiens 96-106 28257907-6 2017 The inhibition constant of kojic acid to free tyrosinase (KI) and kojic acid to tyrosinase/L-DOPA complex (KIS) were calculated to be 36.64 and 74.35 muM, respectively, and the half-maximal inhibitory concentration (IC50) was determined to be 46.64 muM for kojic acid. Levodopa 91-97 tyrosinase Homo sapiens 80-90 27840215-3 2017 Spectrophotometric analysis used to determine the inhibition capabilities of these compounds on tyrosinase catalyzing L-tyrosine (L-Tyr) and L-3,4-Dihydroxyphenylalanine (L-DOPA) as well. Levodopa 171-177 tyrosinase Homo sapiens 96-106 27527415-4 2016 The results of fluorescence quenching experiment showed that the compound could interact with tyrosinase and the substrates (tyrosine and l-DOPA). Levodopa 138-144 tyrosinase Homo sapiens 94-104 29213160-1 2017 The kinetic (KIE) and solvent (SIE) isotope effect methods were used to investigate the mechanism of enzymatic hydroxylation of halogenated derivatives of l-tyrosine to l-DOPA catalyzed by the enzyme tyrosinase (EC 1.14.18.1). Levodopa 169-175 tyrosinase Homo sapiens 200-210 27711193-1 2016 Hydroxylation of L-tyrosine to 3,4-dihydroxyphenylalanine (L-DOPA) by immobilized tyrosinase in the presence of ascorbic acid (AH2), which reduces DOPA-quinone to L-DOPA, is characterized by low reaction yields that are mainly caused by the suicide inactivation of tyrosinase by L-DOPA and AH2. Levodopa 59-65 tyrosinase Homo sapiens 82-92 27711193-1 2016 Hydroxylation of L-tyrosine to 3,4-dihydroxyphenylalanine (L-DOPA) by immobilized tyrosinase in the presence of ascorbic acid (AH2), which reduces DOPA-quinone to L-DOPA, is characterized by low reaction yields that are mainly caused by the suicide inactivation of tyrosinase by L-DOPA and AH2. Levodopa 59-65 tyrosinase Homo sapiens 265-275 27711193-1 2016 Hydroxylation of L-tyrosine to 3,4-dihydroxyphenylalanine (L-DOPA) by immobilized tyrosinase in the presence of ascorbic acid (AH2), which reduces DOPA-quinone to L-DOPA, is characterized by low reaction yields that are mainly caused by the suicide inactivation of tyrosinase by L-DOPA and AH2. Levodopa 163-169 tyrosinase Homo sapiens 82-92 27711193-1 2016 Hydroxylation of L-tyrosine to 3,4-dihydroxyphenylalanine (L-DOPA) by immobilized tyrosinase in the presence of ascorbic acid (AH2), which reduces DOPA-quinone to L-DOPA, is characterized by low reaction yields that are mainly caused by the suicide inactivation of tyrosinase by L-DOPA and AH2. Levodopa 163-169 tyrosinase Homo sapiens 265-275 27711193-1 2016 Hydroxylation of L-tyrosine to 3,4-dihydroxyphenylalanine (L-DOPA) by immobilized tyrosinase in the presence of ascorbic acid (AH2), which reduces DOPA-quinone to L-DOPA, is characterized by low reaction yields that are mainly caused by the suicide inactivation of tyrosinase by L-DOPA and AH2. Levodopa 163-169 tyrosinase Homo sapiens 82-92 27711193-1 2016 Hydroxylation of L-tyrosine to 3,4-dihydroxyphenylalanine (L-DOPA) by immobilized tyrosinase in the presence of ascorbic acid (AH2), which reduces DOPA-quinone to L-DOPA, is characterized by low reaction yields that are mainly caused by the suicide inactivation of tyrosinase by L-DOPA and AH2. Levodopa 163-169 tyrosinase Homo sapiens 265-275 27711193-2 2016 The main aim of this work was to compare processes with native and immobilized tyrosinase to identify the conditions that limit suicide inactivation and produce substrate conversions to L-DOPA of above 50% using HPLC analysis. Levodopa 186-192 tyrosinase Homo sapiens 79-89 27711193-7 2016 A three-fold increase in the bound enzyme load achieved 95% conversion in two successive runs, but in the third one, tyrosinase lost its activity due to strong suicide inactivation caused by L-DOPA processing. Levodopa 191-197 tyrosinase Homo sapiens 117-127 27711193-8 2016 In this case, the cost of the immobilized enzyme preparation is not overcome by its reuse over time, and native tyrosinase may be more economically feasible for a single use in L-DOPA production. Levodopa 177-183 tyrosinase Homo sapiens 112-122 25913862-2 2015 When the monophenolase and the diphenolase activities of tyrosinase on its physiological substrates l-dopa and/or l-tyrosine are measured in the presence of these compounds, the rate of action of the enzyme decreases. Levodopa 100-106 tyrosinase Homo sapiens 57-67 32262068-1 2015 High-intensity fluorescent carbon dots (CDs) coupled with tyrosinase (TYR) yielded hybrids, as a fluorescent probe, which were efficient, fast, stable and sensitive in the detection of levodopa (l-DOPA). Levodopa 185-193 tyrosinase Homo sapiens 58-68 25826232-2 2015 The particles are built up by enzymatic reaction of l-DOPA with tyrosinase. Levodopa 52-58 tyrosinase Homo sapiens 64-74 32262068-1 2015 High-intensity fluorescent carbon dots (CDs) coupled with tyrosinase (TYR) yielded hybrids, as a fluorescent probe, which were efficient, fast, stable and sensitive in the detection of levodopa (l-DOPA). Levodopa 185-193 tyrosinase Homo sapiens 70-73 32262068-1 2015 High-intensity fluorescent carbon dots (CDs) coupled with tyrosinase (TYR) yielded hybrids, as a fluorescent probe, which were efficient, fast, stable and sensitive in the detection of levodopa (l-DOPA). Levodopa 195-201 tyrosinase Homo sapiens 58-68 32262068-1 2015 High-intensity fluorescent carbon dots (CDs) coupled with tyrosinase (TYR) yielded hybrids, as a fluorescent probe, which were efficient, fast, stable and sensitive in the detection of levodopa (l-DOPA). Levodopa 195-201 tyrosinase Homo sapiens 70-73 24912720-7 2014 Moreover, molecular docking results suggested that morin competitively bound to the active site of tyrosinase with the substrate levodopa. Levodopa 129-137 tyrosinase Homo sapiens 99-109 25866725-7 2015 MATERIALS AND METHODS: The inhibitory activities of hydroalcoholic extracts of plants against oxidation of L-Dopa (as a substrate) by mushroom tyrosinase were investigated. Levodopa 107-113 tyrosinase Homo sapiens 143-153 25297374-0 2014 Alleviation effect of arbutin on oxidative stress generated through tyrosinase reaction with L-tyrosine and L-DOPA. Levodopa 108-114 tyrosinase Homo sapiens 68-78 25130058-5 2014 In the presence of a catalytic amount of l-dopa, human tyrosinase, which can oxidize l-tyrosine but not d-tyrosine, was found to oxidize both R(-)- and S(+)-RD to give RD-catechol and its oxidation products. Levodopa 41-47 tyrosinase Homo sapiens 55-65 25297374-4 2014 The aim of the present study was to examine if arbutin could suppress the hydroxyl radical generation via tyrosinase reaction with its substrates, L-tyrosine and L-DOPA. Levodopa 162-168 tyrosinase Homo sapiens 106-116 25297374-5 2014 RESULTS: The hydroxyl radical, which was determined by an electron spin resonance-spin trapping technique, was generated by the addition of not only L-tyrosine but L-DOPA to tyrosinase in a concentration dependent manner. Levodopa 164-170 tyrosinase Homo sapiens 174-184 23403028-0 2013 L-Dopa synthesis catalyzed by tyrosinase immobilized in poly(ethyleneoxide) conducting polymers. Levodopa 0-6 tyrosinase Homo sapiens 30-40 24082892-8 2013 Our results show that all synthesized compounds have inhibitory effect on tyrosinase activity for the oxidation of L-DOPA. Levodopa 115-121 tyrosinase Homo sapiens 74-84 23403028-2 2013 In this study, with regards to the synthesis of L-Dopa two types of biosensors were designed by immobilizing tyrosinase on conducting polymers: thiophene capped poly(ethyleneoxide)/polypyrrole (PEO-co-PPy) and 3-methylthienyl methacrylate-co-p-vinylbenzyloxy poly(ethyleneoxide)/polypyrrole (CP-co-PPy). Levodopa 48-54 tyrosinase Homo sapiens 109-119 23646697-9 2013 The enzymatic assay using L-DOPA and mushroom tyrosinase demonstrated that H2-Silica restrained UVA-mediated melanin formation owing to down-regulation of tyrosinase activity, which could be attributed to scavenging of free radicals and inhibition of L-DOPA-to-dopachrome oxidation by hydrogen released from H2-Silica. Levodopa 26-32 tyrosinase Homo sapiens 155-165 23646697-9 2013 The enzymatic assay using L-DOPA and mushroom tyrosinase demonstrated that H2-Silica restrained UVA-mediated melanin formation owing to down-regulation of tyrosinase activity, which could be attributed to scavenging of free radicals and inhibition of L-DOPA-to-dopachrome oxidation by hydrogen released from H2-Silica. Levodopa 251-257 tyrosinase Homo sapiens 46-56 23646697-9 2013 The enzymatic assay using L-DOPA and mushroom tyrosinase demonstrated that H2-Silica restrained UVA-mediated melanin formation owing to down-regulation of tyrosinase activity, which could be attributed to scavenging of free radicals and inhibition of L-DOPA-to-dopachrome oxidation by hydrogen released from H2-Silica. Levodopa 251-257 tyrosinase Homo sapiens 155-165 22938619-10 2012 This approach also allowed the determination of tyrosinase activity because tyrosinase catalyzes the conversion of l-tyrosine to L-DOPA. Levodopa 129-135 tyrosinase Homo sapiens 48-58 22938619-10 2012 This approach also allowed the determination of tyrosinase activity because tyrosinase catalyzes the conversion of l-tyrosine to L-DOPA. Levodopa 129-135 tyrosinase Homo sapiens 76-86 21054558-3 2011 In human skin melanocytes, the cellular tyrosinase inhibition was examined by the conversion of l-tyrosine and oxidation of l-DOPA to dopaquinone. Levodopa 124-130 tyrosinase Homo sapiens 40-50 22698780-1 2012 In vitro studies, using combined spectrophotometry and oximetry together with hplc/ms examination of the products of tyrosinase action demonstrate that hydroquinone is not a primary substrate for the enzyme but is vicariously oxidised by a redox exchange mechanism in the presence of either catechol, L-3,4-dihydroxyphenylalanine or 4-ethylphenol. Levodopa 301-329 tyrosinase Homo sapiens 117-127 21048351-0 2010 N-(3,5-dihydroxybenzoyl)-6-hydroxytryptamine as a novel human tyrosinase inhibitor that inactivates the enzyme in cooperation with l-3,4-dihydroxyphenylalanine. Levodopa 131-159 tyrosinase Homo sapiens 62-72 21048351-3 2010 Furthermore, compound 2 exhibited a unique property of inactivating the human tyrosinase in the presence of low concentrations of DOPA. Levodopa 130-134 tyrosinase Homo sapiens 78-88 21048351-5 2010 Tyrosinase is the enzyme that oxidizes tyrosine to DOPA and further oxidizes DOPA to the melanin precursor dopaquinone. Levodopa 51-55 tyrosinase Homo sapiens 0-10 21048351-5 2010 Tyrosinase is the enzyme that oxidizes tyrosine to DOPA and further oxidizes DOPA to the melanin precursor dopaquinone. Levodopa 77-81 tyrosinase Homo sapiens 0-10 21048351-6 2010 A compound such as 2 that inactivates the enzyme in the presence of a small amount of DOPA is therefore attractive as a new type of tyrosinase inhibitor. Levodopa 86-90 tyrosinase Homo sapiens 132-142 20215052-1 2010 Under aerobic or anaerobic conditions, tyrosinase undergoes a process of irreversible inactivation induced by its physiological substrate L-dopa. Levodopa 138-144 tyrosinase Homo sapiens 39-49 19440221-9 2009 This inhibition partially depended on whether L-dopa or L-tyrosine was the substrate, suggesting that tyrosinase may contain contains two distinct catalytic sites. Levodopa 46-52 tyrosinase Homo sapiens 102-112 20083145-5 2010 In this study, we developed a novel technology for the production of l-DOPA, an electroenzymatic synthesis with a tyrosinase-immobilized cathode under the reduction potential of DOPAquinone, which is -530 mV. Levodopa 69-75 tyrosinase Homo sapiens 114-124 20355321-6 2010 Kinetic analysis with HMV-II tyrosinase showed that the inhibition by hydroxyindoles 4, 5, and 6 was competitive with respect to the substrate L-DOPA. Levodopa 143-149 tyrosinase Homo sapiens 29-39