PMID-sentid Pub_year Sent_text comp_official_name comp_offsetprotein_name organism prot_offset 9464620-2 1997 Up to 50% inhibition of dopachrome formation was observed in the tyrosinase-dopa reaction in the presence of thiourea at a 2:1 molar ratio with respect to the substrate. Dihydroxyphenylalanine 24-28 tyrosinase Homo sapiens 65-75 10929771-5 2000 We determined the tyrosinase activity in melanocytes by the electron microscopic dihydroxyphenylalanine (EM-DOPA) reaction test using skin samples and analyzed tyrosinase gene mutations in nine Japanese patients with OCA. Dihydroxyphenylalanine 81-103 tyrosinase Homo sapiens 18-28 10929771-11 2000 These results indicate that the EM-DOPA reaction test provides clear information on the status of tyrosinase activity which is essential for the identification of the disease subtype which in turn is important for the prognosis of patients with OCA. Dihydroxyphenylalanine 35-39 tyrosinase Homo sapiens 98-108 10644002-10 1999 Since DOPA functions as a cofactor in the monophenolase reaction of tyrosinase, it is proposed that the ratio of 5-S-CD to DOPA may be an important factor in the regulation of tyrosinase activity in situ. Dihydroxyphenylalanine 6-10 tyrosinase Homo sapiens 68-78 10644002-10 1999 Since DOPA functions as a cofactor in the monophenolase reaction of tyrosinase, it is proposed that the ratio of 5-S-CD to DOPA may be an important factor in the regulation of tyrosinase activity in situ. Dihydroxyphenylalanine 6-10 tyrosinase Homo sapiens 176-186 10506262-3 1999 Within the melanocyte, tyrosine is converted to dopa, and then dopaquinone via the bifunctional enzyme tyrosinase. Dihydroxyphenylalanine 48-52 tyrosinase Homo sapiens 103-113 11460086-3 1999 Melanin is a complex of insoluble, polyquinone, brown or red pigment and protein, formed by the oxidation of tyrosine and 3,4-dihydroxyphenylalanine in the presence of tyrosinase. Dihydroxyphenylalanine 122-148 tyrosinase Homo sapiens 168-178 10644002-10 1999 Since DOPA functions as a cofactor in the monophenolase reaction of tyrosinase, it is proposed that the ratio of 5-S-CD to DOPA may be an important factor in the regulation of tyrosinase activity in situ. Dihydroxyphenylalanine 123-127 tyrosinase Homo sapiens 68-78 10644002-10 1999 Since DOPA functions as a cofactor in the monophenolase reaction of tyrosinase, it is proposed that the ratio of 5-S-CD to DOPA may be an important factor in the regulation of tyrosinase activity in situ. Dihydroxyphenylalanine 123-127 tyrosinase Homo sapiens 176-186 10491588-8 1999 Faster kinetics were observed when Dopa was treated with tyrosinase, the enzyme catalysing the oligomerization of tyrosine to melanins, leading to the formation mainly of DHI oligomers. Dihydroxyphenylalanine 35-39 tyrosinase Homo sapiens 57-67 9820172-5 1998 In addition, we used the DOPA reaction to detect tyrosinase enzyme activity as a confirmation of the tyrosinase immunohistochemical results. Dihydroxyphenylalanine 25-29 tyrosinase Homo sapiens 49-59 9029814-1 1996 The various theories put forward to explain the characteristic lag kinetics of oxidation of L-tyrosine by tyrosinase a rate regulatory step in the biosynthesis of melanin are reviewed Examination of the evidence in the literature and from experiments in the author"s laboratory indicate that one of the hypotheses, that is, competition of tyrosine and dopa for met-tyrosinase and the formation of a dead-end complex of met-enzyme with tyrosine as explanation for lag kinetics is not consistent with available information. Dihydroxyphenylalanine 352-356 tyrosinase Homo sapiens 106-116 9367182-5 1997 We prepared pheomelanins by tyrosinase oxidation of dopa or tyrosine in the presence of cysteine. Dihydroxyphenylalanine 52-56 tyrosinase Homo sapiens 28-38 9059668-3 1997 Subsequent introduction of the electron microscopic DOPA reaction test in fetal skin provided safer, more practical, and reliable information for diagnosing tyrosinase-negative oculocutaneous albinism prenatally. Dihydroxyphenylalanine 52-56 tyrosinase Homo sapiens 157-167 9029814-2 1996 The alternative hypothesis that tyrosinase is an allosteric enzyme with tyrosine having negative effector site on the enzyme and dopa competing for it as an explanation for lag kinetics of tyrosinase is not yet disproved. Dihydroxyphenylalanine 129-133 tyrosinase Homo sapiens 32-42 9029814-2 1996 The alternative hypothesis that tyrosinase is an allosteric enzyme with tyrosine having negative effector site on the enzyme and dopa competing for it as an explanation for lag kinetics of tyrosinase is not yet disproved. Dihydroxyphenylalanine 129-133 tyrosinase Homo sapiens 189-199 8857672-9 1996 Furthermore, formation of dopa occurred in a xanthine/xanthine oxidase system when bovine serum albumin (BSA) was substituted for tyrosinase. Dihydroxyphenylalanine 26-30 tyrosinase Homo sapiens 130-140 8248014-3 1993 Tyrosinase is a highly unusual enzyme in that it apparently catalyses two processes, i.e., the oxidation of tyrosine and the dehydrogenation of dihydroxyphenylalanine (Dopa), at the same active site. Dihydroxyphenylalanine 144-166 tyrosinase Homo sapiens 0-10 8578949-4 1995 Tyrosinase has high stereo-specificity for the L-enantiomer of dopa, and correction for non-specific oxidation was made by simultaneous measurement of 5-S-L-cysteinyl-D-dopa formed from D-dopa. Dihydroxyphenylalanine 63-67 tyrosinase Homo sapiens 0-10 7659677-5 1995 DHI inhibits both activities of tyrosinase--tyrosine-hydroxylation and DOPA-oxidation--more strongly than DHICA. Dihydroxyphenylalanine 71-75 tyrosinase Homo sapiens 32-42 7827110-4 1995 The concomitant oxidation of dopa and opioid peptides by tyrosinase produces mixed polymers, showing the distinctive absorption peak at 330 nm. Dihydroxyphenylalanine 29-33 tyrosinase Homo sapiens 57-67 7937580-0 1994 Prenatal diagnosis of tyrosinase-negative oculocutaneous albinism by an electron microscopic dopa reaction test of fetal skin. Dihydroxyphenylalanine 93-97 tyrosinase Homo sapiens 22-32 7937580-1 1994 An electron microscopic DOPA reaction test of fetal skin was used for the prenatal diagnosis of tyrosinase-negative oculocutaneous albinism (OCA). Dihydroxyphenylalanine 24-28 tyrosinase Homo sapiens 96-106 7937580-10 1994 This study shows that tyrosinase is normally present in melanocytes of the fetal epidermis at 20 weeks" gestation, and that the electron microscopic DOPA reaction test of a fetal skin biopsy specimen is safe and practical, and provides reliable information for making a prenatal diagnosis of tyrosinase-negative OCA in the second trimester. Dihydroxyphenylalanine 149-153 tyrosinase Homo sapiens 292-302 8224374-0 1993 The effect of tryptophan on dopa-oxidation by melanosomal tyrosinase. Dihydroxyphenylalanine 28-32 tyrosinase Homo sapiens 58-68 8224374-2 1993 Tryptophan has been shown to inhibit dopa-oxidation by melanosomal tyrosinase. Dihydroxyphenylalanine 37-41 tyrosinase Homo sapiens 67-77 8224374-9 1993 Tryptophan, like dopa, also inhibits tyrosine hydroxylase and dopa-oxidase activity of melanosomal tyrosinase and its inhibitory mechanism differs from inhibition due to non-substrate type compounds like cysteine, ascorbic acid. Dihydroxyphenylalanine 17-21 tyrosinase Homo sapiens 99-109 8248014-3 1993 Tyrosinase is a highly unusual enzyme in that it apparently catalyses two processes, i.e., the oxidation of tyrosine and the dehydrogenation of dihydroxyphenylalanine (Dopa), at the same active site. Dihydroxyphenylalanine 168-172 tyrosinase Homo sapiens 0-10 1476926-2 1992 An electron microscopic tyrosine incubation test and a DOPA reaction test clearly demonstrated the presence of tyrosinase activity in the patient"s hypopigmented skin. Dihydroxyphenylalanine 55-59 tyrosinase Homo sapiens 111-121 8433013-3 1993 This study proposed to undertake a systemic approach to the chemotherapy of malignant melanoma based upon the uniqueness of pigment-cell metabolic pathway pertaining to conversion of tyrosine and dopa with subsequent formation of melanin by tyrosinase and its related enzymes. Dihydroxyphenylalanine 196-200 tyrosinase Homo sapiens 241-251 1445949-1 1992 The oxidation of 3,4-dihydroxyphenylalanine (dopa) by O2 catalyzed by tyrosinase yields 4-(2-carboxy-2-aminoethyl)-1,2-benzoquinone, with its amino group protonated (o-dopaquinone-H+). Dihydroxyphenylalanine 17-43 tyrosinase Homo sapiens 70-80 1445949-1 1992 The oxidation of 3,4-dihydroxyphenylalanine (dopa) by O2 catalyzed by tyrosinase yields 4-(2-carboxy-2-aminoethyl)-1,2-benzoquinone, with its amino group protonated (o-dopaquinone-H+). Dihydroxyphenylalanine 45-49 tyrosinase Homo sapiens 70-80 1309977-5 1992 Since the addition of H2O2 and dopa to tyrosinase promotes the release of O2- and formation of dopachrome, the Cu(II)O2-Cu(I) complex could be formed as a intermediate (an active form of tyrosinase); [Cu(II)]2 + H2O2 in equilibrium Cu(I)O2-Cu(II) + 2H+. Dihydroxyphenylalanine 31-35 tyrosinase Homo sapiens 39-49 1316167-5 1992 It is suggested that the incorporation of estrogens into melanin produced by mammalian tyrosinase is via their oxidation by oxidized intermediates of the dopa to melanin transformation. Dihydroxyphenylalanine 154-158 tyrosinase Homo sapiens 87-97 1740428-9 1992 This low value explains the lower catalytic efficiency of tyrosinase on tyrosine than on dopa, (VmaxT/KmT)/(VmaxD/KmD) congruent to (2/3)R, since a significant portion of tyrosinase is scavenged from the catalytic turnover as dead-end complex EmetT in the steady-state of the monophenolase activity of tyrosinase. Dihydroxyphenylalanine 89-93 tyrosinase Homo sapiens 58-68 1740428-9 1992 This low value explains the lower catalytic efficiency of tyrosinase on tyrosine than on dopa, (VmaxT/KmT)/(VmaxD/KmD) congruent to (2/3)R, since a significant portion of tyrosinase is scavenged from the catalytic turnover as dead-end complex EmetT in the steady-state of the monophenolase activity of tyrosinase. Dihydroxyphenylalanine 89-93 tyrosinase Homo sapiens 171-181 1740428-9 1992 This low value explains the lower catalytic efficiency of tyrosinase on tyrosine than on dopa, (VmaxT/KmT)/(VmaxD/KmD) congruent to (2/3)R, since a significant portion of tyrosinase is scavenged from the catalytic turnover as dead-end complex EmetT in the steady-state of the monophenolase activity of tyrosinase. Dihydroxyphenylalanine 89-93 tyrosinase Homo sapiens 171-181 1309977-5 1992 Since the addition of H2O2 and dopa to tyrosinase promotes the release of O2- and formation of dopachrome, the Cu(II)O2-Cu(I) complex could be formed as a intermediate (an active form of tyrosinase); [Cu(II)]2 + H2O2 in equilibrium Cu(I)O2-Cu(II) + 2H+. Dihydroxyphenylalanine 31-35 tyrosinase Homo sapiens 187-197 2127180-1 1990 Phosphonic acid and phosphinic acid analogues of tyrosine and 3,4-dihydroxyphenylalanine (dopa) were found to influence tyrosinase activity, thus being potential regulators of melanization in mammalian cells. Dihydroxyphenylalanine 62-88 tyrosinase Homo sapiens 120-130 1901069-2 1991 A dopa reaction test in hair bulbs from the scalp of normal fetuses obtained after abortion showed that tyrosinase is present in fetuses as early as 17 weeks. Dihydroxyphenylalanine 2-6 tyrosinase Homo sapiens 104-114 1899343-4 1991 Kinetic investigations showed that HQ is a poorer substrate of tyrosinase than tyrosine; yet, it may be effectively oxidised in the presence of tyrosine owing to the generation of catalytic amounts of dopa acting as cofactor of tyrosinase. Dihydroxyphenylalanine 201-205 tyrosinase Homo sapiens 63-73 1899343-4 1991 Kinetic investigations showed that HQ is a poorer substrate of tyrosinase than tyrosine; yet, it may be effectively oxidised in the presence of tyrosine owing to the generation of catalytic amounts of dopa acting as cofactor of tyrosinase. Dihydroxyphenylalanine 201-205 tyrosinase Homo sapiens 228-238 1899343-5 1991 Product analysis of HQ oxidation with tyrosinase in the presence of dopa showed the predominant formation in the early stages of hydroxybenzoquinone (HBQ), arising from enzymic hydroxylation and subsequent oxidation of HQ, along with lower amounts of benzoquinone (BQ). Dihydroxyphenylalanine 68-72 tyrosinase Homo sapiens 38-48 2121652-5 1990 In a previous in vitro study, it was shown that 4-S-CP and 4-S-CAP required a catalytic amount of dopa for optimal mammalian tyrosinase activity. Dihydroxyphenylalanine 98-102 tyrosinase Homo sapiens 125-135 2127180-1 1990 Phosphonic acid and phosphinic acid analogues of tyrosine and 3,4-dihydroxyphenylalanine (dopa) were found to influence tyrosinase activity, thus being potential regulators of melanization in mammalian cells. Dihydroxyphenylalanine 90-94 tyrosinase Homo sapiens 120-130 1969915-4 1990 The unexpected increase of DOPA (progressively more converted toward DOPA sulfate) in the presence of tyrosine hydroxylase inhibition and increase in tyrosine may result from channeling the excess tyrosine toward DOPA and melanin through tyrosinase. Dihydroxyphenylalanine 27-31 tyrosinase Homo sapiens 238-248 1969915-4 1990 The unexpected increase of DOPA (progressively more converted toward DOPA sulfate) in the presence of tyrosine hydroxylase inhibition and increase in tyrosine may result from channeling the excess tyrosine toward DOPA and melanin through tyrosinase. Dihydroxyphenylalanine 69-73 tyrosinase Homo sapiens 238-248 34757293-0 2021 Genetically encoded dihydroxyphenylalanine coupled with tyrosinase for strain promoted labeling. Dihydroxyphenylalanine 20-42 tyrosinase Homo sapiens 56-66 33804376-1 2021 Tyrosinase is a copper-containing monooxygenase catalyzing the O-hydroxylation of tyrosine to 3,4-dihydroxyphenylalanine then to dopaquinone that is profoundly involved in melanin synthesis in eukaryotes. Dihydroxyphenylalanine 94-120 tyrosinase Homo sapiens 0-10 3131764-1 1988 We have examined the rate of synthesis and degradation of tyrosinase (monophenol, 3,4-dihydroxyphenylalanine:oxygen oxidoreductase, EC 1.14.18.1), the critical enzyme involved in mammalian pigmentation, using pulse-chase metabolic labeling of murine melanoma cells and immunoprecipitation of protein extracts with antibodies directed specifically against the enzyme. Dihydroxyphenylalanine 82-108 tyrosinase Homo sapiens 58-68 2517578-3 1989 Aminoacid analysis after hydrolysis of long-lasting incubation mixtures of tyrosinase with Leu-enkephalin in presence of reductants demonstrates the formation of DOPA. Dihydroxyphenylalanine 162-166 tyrosinase Homo sapiens 75-85 2564228-6 1989 A dopa-reactive band with an apparent MW of 66 kD was present in the gel, i.e. at the same place as that of the soluble tyrosinase of cultured human malignant melanoma cells. Dihydroxyphenylalanine 2-6 tyrosinase Homo sapiens 120-130 2903772-3 1988 (a) The reaction of the thiol groups with dopaquinone after the tyrosinase-catalyzed oxidation of tyrosine and dopa. Dihydroxyphenylalanine 42-46 tyrosinase Homo sapiens 64-74 3036239-0 1987 Tyrosinase-catalyzed oxidation of dopa and related catechol(amine)s: a kinetic electron spin resonance investigation using spin-stabilization and spin label oximetry. Dihydroxyphenylalanine 34-38 tyrosinase Homo sapiens 0-10 3123559-5 1988 Dopa cytochemistry revealed that the distribution of MoAb HMSA-1 reaction product is localized in the area different from that of tyrosinase, indicating that the synthetic processes of melanosomal matrix protein and tyrosinase are different. Dihydroxyphenylalanine 0-4 tyrosinase Homo sapiens 216-226 2438872-6 1987 The ratio between 2-S-cysteinyldopa and 5-S-cysteinyldopa when incubating dopa and cysteine with tyrosinase was identical with the ratio between the analogically synthetised isomers of glutathionyldopa. Dihydroxyphenylalanine 31-35 tyrosinase Homo sapiens 97-107 2938636-0 1986 Tyrosinase-catalyzed binding of 3,4-dihydroxyphenylalanine with proteins through the sulfhydryl group. Dihydroxyphenylalanine 32-58 tyrosinase Homo sapiens 0-10 2938636-2 1986 The nature of the covalent binding was studied with dopaquinone formed on tyrosinase oxidation of 3,4-dihydroxyphenylalanine (DOPA). Dihydroxyphenylalanine 98-124 tyrosinase Homo sapiens 74-84 2938636-2 1986 The nature of the covalent binding was studied with dopaquinone formed on tyrosinase oxidation of 3,4-dihydroxyphenylalanine (DOPA). Dihydroxyphenylalanine 126-130 tyrosinase Homo sapiens 74-84 3924652-0 1985 Tyrosinase-catalyzed conjugation of dopa with glutathione. Dihydroxyphenylalanine 36-40 tyrosinase Homo sapiens 0-10 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. Dihydroxyphenylalanine 20-24 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. Dihydroxyphenylalanine 20-24 tyrosinase Homo sapiens 164-174 3103358-1 1986 5-S-Glutathionyldopa is oxidized at incubation with tyrosinase and dopa producing a black pigment. Dihydroxyphenylalanine 16-20 tyrosinase Homo sapiens 52-62 3924652-1 1985 A convenient method is described for the preparation of 5-S- and 2-S-glutathionyldopa, based on tyrosinase oxidation of dopa in the presence of glutathione. Dihydroxyphenylalanine 81-85 tyrosinase Homo sapiens 96-106 3927772-3 1985 Final absorbance change reflects probably two activities of tyrosinase: the oxidation of dopa to dopaquinone and the conversion of 5,6-dihydroxyindole to melanochrome. Dihydroxyphenylalanine 89-93 tyrosinase Homo sapiens 60-70 3927896-1 1985 The conversion of tyrosine into dopa [3-(3,4-dihydroxyphenyl)alanine] is the rate limiting step in the biosynthesis of melanins catalysed by tyrosinase. Dihydroxyphenylalanine 32-36 tyrosinase Homo sapiens 141-151 3927896-1 1985 The conversion of tyrosine into dopa [3-(3,4-dihydroxyphenyl)alanine] is the rate limiting step in the biosynthesis of melanins catalysed by tyrosinase. Dihydroxyphenylalanine 38-68 tyrosinase Homo sapiens 141-151 6198834-0 1983 Dopa oxidation and tyrosine oxygenation by human melanoma tyrosinase. Dihydroxyphenylalanine 0-4 tyrosinase Homo sapiens 58-68 6410161-2 1983 The enzyme tyrosinase oxidizes tyrosine to DOPA and also catalizes the oxidation of DOPA to Melanin. Dihydroxyphenylalanine 43-47 tyrosinase Homo sapiens 11-21 6410161-2 1983 The enzyme tyrosinase oxidizes tyrosine to DOPA and also catalizes the oxidation of DOPA to Melanin. Dihydroxyphenylalanine 84-88 tyrosinase Homo sapiens 11-21 6203305-5 1984 Dopa and/or tyrosine protects tyrosinase against inactivation by cysteine. Dihydroxyphenylalanine 0-4 tyrosinase Homo sapiens 30-40 6810464-1 1982 The biosynthesis of melanin is initiated by the catalytic oxidation of tyrosine to dopa by tyrosinase in a reaction that requires dopa as a cofactor. Dihydroxyphenylalanine 83-87 tyrosinase Homo sapiens 91-101 6410541-0 1983 False dopa reaction in studies of mammalian tyrosinase: some characteristics and precautions. Dihydroxyphenylalanine 6-10 tyrosinase Homo sapiens 44-54 6810464-1 1982 The biosynthesis of melanin is initiated by the catalytic oxidation of tyrosine to dopa by tyrosinase in a reaction that requires dopa as a cofactor. Dihydroxyphenylalanine 130-134 tyrosinase Homo sapiens 91-101 6165191-1 1981 The recently discovered intermediate product in melanin formation, 5-OH-dopa, is formed in large amounts when dopa is oxidized by tyrosinase in the presence of ascorbic acid. Dihydroxyphenylalanine 72-76 tyrosinase Homo sapiens 130-140 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. Dihydroxyphenylalanine 224-228 tyrosinase Homo sapiens 0-10 6774805-8 1980 Although the binding of estradiol to tyrosinase was inhibited by DOPA, the binding of estradiol to estrogen receptor preparations was not. Dihydroxyphenylalanine 65-69 tyrosinase Homo sapiens 37-47 6775084-8 1980 TBC and hydroquinone are inhibitors of tyrosinase at concentrations higher than 1 x 10(-3) M. Dopa and tyrosine alter tyrosinase activity in the second step of melanogenesis in the same manner that has been reported to occur in the first step-conversion of tyrosine to dopa. Dihydroxyphenylalanine 94-98 tyrosinase Homo sapiens 39-49 6775084-8 1980 TBC and hydroquinone are inhibitors of tyrosinase at concentrations higher than 1 x 10(-3) M. Dopa and tyrosine alter tyrosinase activity in the second step of melanogenesis in the same manner that has been reported to occur in the first step-conversion of tyrosine to dopa. Dihydroxyphenylalanine 94-98 tyrosinase Homo sapiens 118-128 6775084-8 1980 TBC and hydroquinone are inhibitors of tyrosinase at concentrations higher than 1 x 10(-3) M. Dopa and tyrosine alter tyrosinase activity in the second step of melanogenesis in the same manner that has been reported to occur in the first step-conversion of tyrosine to dopa. Dihydroxyphenylalanine 269-273 tyrosinase Homo sapiens 39-49 6775084-8 1980 TBC and hydroquinone are inhibitors of tyrosinase at concentrations higher than 1 x 10(-3) M. Dopa and tyrosine alter tyrosinase activity in the second step of melanogenesis in the same manner that has been reported to occur in the first step-conversion of tyrosine to dopa. Dihydroxyphenylalanine 269-273 tyrosinase Homo sapiens 118-128 6163271-1 1980 Oxidation of tyrosine or dopa by tyrosinase leads to the formation of 5-OH-dopa, a compound previously unknown in melanogenesis. Dihydroxyphenylalanine 25-29 tyrosinase Homo sapiens 33-43 6163271-2 1980 5-OH-dopa, first detected as an unknown compound on HPLC of the dopa-tyrosinase incubate, was purified by Al2O3-adsorption, semipreparative HPLC, and ion-exchange chromatography. Dihydroxyphenylalanine 5-9 tyrosinase Homo sapiens 69-79 326027-6 1977 All three tumors were positive in the DOPA test, suggesting the presence of tyrosinase within the tumor cells. Dihydroxyphenylalanine 38-42 tyrosinase Homo sapiens 76-86 99481-1 1978 Lipid fractions capable of inhibiting the dopa-tyrosinase reaction in vitro were isolated by thin-layer chromatography from submerged cultures of Pityrosporum supplemented with oleic acid or vaccenic acid. Dihydroxyphenylalanine 42-46 tyrosinase Homo sapiens 47-57 405430-3 1977 The ultrastructural localization of tyrosinase, the enzyme which converts tyrosine and dopa into melanin, was determined in 13 human melanoma cell lines. Dihydroxyphenylalanine 87-91 tyrosinase Homo sapiens 36-46 825109-9 1976 Further, dopa appears to act as a positive allosteric effector for tyrosine hydroxylation by tyrosinase, in addition to its known activity as a hydrogen donor for the reaction. Dihydroxyphenylalanine 9-13 tyrosinase Homo sapiens 93-103 182176-0 1976 Effect of penicillamine on the conversion of dopa to dopachrome in the presence of tyrosinase or ceruloplasmin. Dihydroxyphenylalanine 45-49 tyrosinase Homo sapiens 83-93 50762-1 1975 Quantitative differences in the tyrosinase activity are found at the three types of malignant melanoma of Clark and Mihm by the combined 3,4-dihydroxyphenylalanine-premelanin-reaction. Dihydroxyphenylalanine 137-163 tyrosinase Homo sapiens 32-42 808174-3 1975 The tyrosinase band (Dopa stained) was transformed into a new less anodic form, similar to tyrosinase T2, on disc electrophoresis. Dihydroxyphenylalanine 21-25 tyrosinase Homo sapiens 4-14 808174-3 1975 The tyrosinase band (Dopa stained) was transformed into a new less anodic form, similar to tyrosinase T2, on disc electrophoresis. Dihydroxyphenylalanine 21-25 tyrosinase Homo sapiens 91-101 18133389-0 1949 The chemistry of melanin; oxidation of dihydroxyphenylalanine by tyrosinase. Dihydroxyphenylalanine 39-61 tyrosinase Homo sapiens 65-75 4971287-5 1968 The lens proteins lose their thiol groups and, in acid hydrolysates of treated beta-and gamma-crystallins, a substance has been detected chromatographically that behaves similarly to a compound formed when 3,4-dihydroxyphenylalanine (dopa) is oxidized by tyrosinase in the presence of cysteine. Dihydroxyphenylalanine 206-232 tyrosinase Homo sapiens 255-265 4961079-0 1966 Identification of 3,4-dihydroxyphenylalanine as tyrosinase cofactor in melanoma. Dihydroxyphenylalanine 18-44 tyrosinase Homo sapiens 48-58 18920770-0 1948 The chemistry of melanin; mechanism of the oxidation of dihydroxyphenylalanine by tyrosinase. Dihydroxyphenylalanine 56-78 tyrosinase Homo sapiens 82-92 30843382-3 2019 In this study, with synthetic biology strategy, recombinant mussel plaque protein with a zwitterionic peptide inspired by molecular chaperone was engineered through post-translational modification, in which 3,4-dihydroxyphenylalanine was residue-specifically obtained efficiently from tyrosine with tyrosinase coexpressed in vivo. Dihydroxyphenylalanine 207-233 tyrosinase Homo sapiens 299-309 32776353-0 2021 Study of tyrosine and dopa enantiomers as tyrosinase substrates initiating L- and D-melanogenesis pathways. Dihydroxyphenylalanine 22-26 tyrosinase Homo sapiens 42-52 32776353-1 2021 Tyrosinase starts melanogenesis and determines its course, catalysing the oxidation by molecular oxygen of tyrosine to dopa, and that of dopa to dopaquinone. Dihydroxyphenylalanine 119-123 tyrosinase Homo sapiens 0-10 32776353-1 2021 Tyrosinase starts melanogenesis and determines its course, catalysing the oxidation by molecular oxygen of tyrosine to dopa, and that of dopa to dopaquinone. Dihydroxyphenylalanine 137-141 tyrosinase Homo sapiens 0-10 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. Dihydroxyphenylalanine 88-92 tyrosinase Homo sapiens 14-24 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. Dihydroxyphenylalanine 157-161 tyrosinase Homo sapiens 0-10 31372740-4 2019 Activity of tyrosinase was measured by the DOPA oxidation method. Dihydroxyphenylalanine 43-47 tyrosinase Homo sapiens 12-22 30994696-6 2019 The enzyme tyrosinase oxidises tyrosine into 3,4-dihydroxyphenylalanine (DOPA), DOPA-quinone and further products, eventually forming eumelanin. Dihydroxyphenylalanine 45-71 tyrosinase Homo sapiens 11-21 30994696-6 2019 The enzyme tyrosinase oxidises tyrosine into 3,4-dihydroxyphenylalanine (DOPA), DOPA-quinone and further products, eventually forming eumelanin. Dihydroxyphenylalanine 73-77 tyrosinase Homo sapiens 11-21 29283382-3 2017 Tyrosinase catalyses two successive oxidations in melanin biosynthesis: the conversions of tyrosine to dihydroxyphenylalanine (DOPA) and DOPA to dopaquinone. Dihydroxyphenylalanine 103-125 tyrosinase Homo sapiens 0-10 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. Dihydroxyphenylalanine 92-118 tyrosinase Homo sapiens 18-28 29223142-3 2018 Tyrosinase is a key enzyme in melanin synthesis, which regulates the rate-limiting step during conversion of tyrosine into DOPA and dopaquinone. Dihydroxyphenylalanine 123-127 tyrosinase Homo sapiens 0-10 29283382-3 2017 Tyrosinase catalyses two successive oxidations in melanin biosynthesis: the conversions of tyrosine to dihydroxyphenylalanine (DOPA) and DOPA to dopaquinone. Dihydroxyphenylalanine 127-131 tyrosinase Homo sapiens 0-10 29283382-3 2017 Tyrosinase catalyses two successive oxidations in melanin biosynthesis: the conversions of tyrosine to dihydroxyphenylalanine (DOPA) and DOPA to dopaquinone. Dihydroxyphenylalanine 137-141 tyrosinase Homo sapiens 0-10 27657049-4 2016 Tyrosinase catalyzes the oxidation of tyrosine as well as dopa to dopaquinone. Dihydroxyphenylalanine 58-62 tyrosinase Homo sapiens 0-10 28271633-6 2017 We found that pheomelanin production either from dopa or tyrosine in the presence of cysteine by tyrosinase was greatest at pH values of 5.8-6.3, while eumelanin production was suppressed at pH 5.8. Dihydroxyphenylalanine 49-53 tyrosinase Homo sapiens 97-107 27769941-7 2017 Tyrosinase catalyzes the oxidation of tyrosine into dihydroxyphenylalanine (DOPA), DOPA quinone, and finally into DOPA dimer. Dihydroxyphenylalanine 52-74 tyrosinase Homo sapiens 0-10 27769941-7 2017 Tyrosinase catalyzes the oxidation of tyrosine into dihydroxyphenylalanine (DOPA), DOPA quinone, and finally into DOPA dimer. Dihydroxyphenylalanine 76-80 tyrosinase Homo sapiens 0-10 27769941-7 2017 Tyrosinase catalyzes the oxidation of tyrosine into dihydroxyphenylalanine (DOPA), DOPA quinone, and finally into DOPA dimer. Dihydroxyphenylalanine 83-87 tyrosinase Homo sapiens 0-10 27769941-17 2017 Although tyrosinase has been used for hydrogel crosslinking and in situ cell encapsulation, to the best of our knowledge tyrosinase-mediated DOPA formation has not been explored for in situ stiffening of cell-laden hydrogels. Dihydroxyphenylalanine 141-145 tyrosinase Homo sapiens 121-131 27448544-2 2016 Herein we report a convenient and highly sensitive fluorometric biosensor for tyrosinase activity detection based on biocompatible dopamine-functionalized Au/Ag nanoclusters (Dopa-Au/Ag NCs). Dihydroxyphenylalanine 175-179 tyrosinase Homo sapiens 78-88 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. Dihydroxyphenylalanine 31-57 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. Dihydroxyphenylalanine 31-57 tyrosinase Homo sapiens 265-275 20077437-7 2010 Enzyme kinetics analysis indicated that p-CA is a mixed type (for tyrosine) or competitive inhibitor (for DOPA) of human TYR. Dihydroxyphenylalanine 106-110 tyrosinase Homo sapiens 121-124 26596215-8 2016 Dopa colorimetry was performed to analyze TYR activity. Dihydroxyphenylalanine 0-4 tyrosinase Homo sapiens 42-45 26440479-2 2015 In this work, we develop a convenient and real-time assay with high sensitivity for TYR activity/level monitoring and its inhibitor screening based on biocompatible dopamine functionalized carbon quantum dots (Dopa-CQDs). Dihydroxyphenylalanine 210-214 tyrosinase Homo sapiens 84-87 26440479-4 2015 When the dopamine moiety in Dopa-CQDs conjugate was oxidized to a dopaquinone derivative under specific catalysis of TYR, an intraparticle photoinduced electron transfer (PET) process between CQDs and dopaquinone moiety took place, and then the fluorescence of the conjugate could be quenched simultaneously. Dihydroxyphenylalanine 28-32 tyrosinase Homo sapiens 117-120 26440479-8 2015 It is also demonstrated that Dopa-CQD conjugate possesses excellent biocompatibility, and can sensitively monitor intracellular tyrosinase level in melanoma cells and intracellular pH changes in living cells, which provides great potential in application of TYR/pH-associated disease monitoring and medical diagnostics. Dihydroxyphenylalanine 29-33 tyrosinase Homo sapiens 128-138 26440479-8 2015 It is also demonstrated that Dopa-CQD conjugate possesses excellent biocompatibility, and can sensitively monitor intracellular tyrosinase level in melanoma cells and intracellular pH changes in living cells, which provides great potential in application of TYR/pH-associated disease monitoring and medical diagnostics. Dihydroxyphenylalanine 29-33 tyrosinase Homo sapiens 258-261 32261607-4 2014 The tyrosine residues in human gelatin were converted into DOPA by enzymatic reaction with tyrosinase. Dihydroxyphenylalanine 59-63 tyrosinase Homo sapiens 91-101 22187676-1 2011 Under aerobic conditions, tyrosinase is inactivated by dopa as a result of suicide inactivation, and, under anaerobic conditions, as a result of irreversible inactivation. Dihydroxyphenylalanine 55-59 tyrosinase Homo sapiens 26-36 11963989-3 2002 This compound inhibited the tyrosinase activity, which converts dopa to dopachrome in the biosynthetic process of melanin, and showed a UV-blocking effect at UV-B band. Dihydroxyphenylalanine 64-68 tyrosinase Homo sapiens 28-38 20480001-2 2010 Although such quinone derivatives are usually produced via the autoxidation of catecholamines, tyrosinase, which is a key enzyme in melanin biosynthesis via the production of DOPA and subsequent molecules, can potentially accelerate the induction of catecholamine quinone derivatives by its oxidase activity. Dihydroxyphenylalanine 175-179 tyrosinase Homo sapiens 95-105 19493317-1 2009 Pheomelanogenesis is a complex pathway that starts with the oxidation of tyrosine (or DOPA, 3,4-dihydroxyphenylalanine) by tyrosinase in the presence of cysteine, which results in the production of 5-S-cysteinyldopa and its isomers. Dihydroxyphenylalanine 86-90 tyrosinase Homo sapiens 123-133 19493317-1 2009 Pheomelanogenesis is a complex pathway that starts with the oxidation of tyrosine (or DOPA, 3,4-dihydroxyphenylalanine) by tyrosinase in the presence of cysteine, which results in the production of 5-S-cysteinyldopa and its isomers. Dihydroxyphenylalanine 92-118 tyrosinase Homo sapiens 123-133 19502746-5 2009 In the case of tyrosinase, the values of the Michaelis constant for both substrates were greater than those described for dopa, although the catalytic constants were lower, probably due to the greater size of the substitute group in carbon 1. Dihydroxyphenylalanine 122-126 tyrosinase Homo sapiens 15-25 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. Dihydroxyphenylalanine 149-153 tyrosinase Homo sapiens 78-88 14767648-2 2004 METHODS: Synthetic melanin was prepared from dopa by the action of tyrosinase. Dihydroxyphenylalanine 45-49 tyrosinase Homo sapiens 67-77 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). Dihydroxyphenylalanine 383-409 tyrosinase Homo sapiens 224-234 14511124-2 2003 Although such quinone derivatives are usually produced via the autoxidation of catecholamines, tyrosinase, which is a key enzyme in melanin biosynthesis via the production of DOPA and subsequent molecules, may potentially accelerate the induction of catecholamine quinone derivatives by its oxidase activity. Dihydroxyphenylalanine 175-179 tyrosinase Homo sapiens 95-105 14511124-4 2003 Overexpression of tyrosinase in cultured cell lines resulted in (i) increased intracellular dopamine content; (ii) induction of oxidase activity not only for DOPA but also for dopamine; (iii) formation of melanin pigments in cell soma; and (iv) increased intracellular reactive oxygen species. Dihydroxyphenylalanine 158-162 tyrosinase Homo sapiens 18-28 12190874-6 2002 Incubation of transfected melanocytes with DOPA (the cofactor and substrate for tyrosinase), or tyrosine (the substrate), further enhanced processing of ectopic mutant proteins. Dihydroxyphenylalanine 43-47 tyrosinase Homo sapiens 80-90 20215052-0 2010 Tyrosinase inactivation in its action on dopa. Dihydroxyphenylalanine 41-45 tyrosinase Homo sapiens 0-10 19684380-10 2009 CONCLUSION: DOPA-GA reflects tyrosinase activity in melanocytic tumours, and our new approach is an improvement on the conventional DOPA oxidase method, with regard to both specificity and sensitivity. Dihydroxyphenylalanine 12-16 tyrosinase Homo sapiens 29-39 17978489-5 2007 The compounds also significantly inhibited the activity of tyrosinase, the enzyme that converts DOPA (3,4-dihydroxyphenylalanine) to dopachrome in the biosynthetic process of melanin. Dihydroxyphenylalanine 96-100 tyrosinase Homo sapiens 59-69 17978489-5 2007 The compounds also significantly inhibited the activity of tyrosinase, the enzyme that converts DOPA (3,4-dihydroxyphenylalanine) to dopachrome in the biosynthetic process of melanin. Dihydroxyphenylalanine 102-128 tyrosinase Homo sapiens 59-69 15885091-0 2005 Production and utilization of hydrogen peroxide associated with melanogenesis and tyrosinase-mediated oxidations of DOPA and dopamine. Dihydroxyphenylalanine 116-120 tyrosinase Homo sapiens 82-92 15885091-4 2005 There was no evidence to suggest that H(2)O(2) or any other ROI was produced during the tyrosinase-mediated conversion of tyrosine to DOPA (monophenolase activity). Dihydroxyphenylalanine 134-138 tyrosinase Homo sapiens 88-98 14746615-6 2004 Tyrosinase from HM3KO cells was used to measure the direct effect of DLC on DOPA and DOPAchrome production. Dihydroxyphenylalanine 76-80 tyrosinase Homo sapiens 0-10 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). Dihydroxyphenylalanine 220-246 tyrosinase Homo sapiens 41-51 11564171-9 2001 Electron microscope analysis of the A-188 cells revealed that absence of HPS1 protein resulted in the deposition of dihydroxyphenylalanine reaction products (i.e., tyrosinase) confined to large membrane-bound structures with limiting membranes. Dihydroxyphenylalanine 116-138 tyrosinase Homo sapiens 164-174 12444326-3 2002 However, it is now believed that tyrosinase is responsible for the conversion of tyrosine to dopa and of dopa to dopaquinone, and that peroxidase accomplishes the oxidative polymerization of the eventually formed indoles to eumelanin pigments. Dihydroxyphenylalanine 93-97 tyrosinase Homo sapiens 33-43 12444326-3 2002 However, it is now believed that tyrosinase is responsible for the conversion of tyrosine to dopa and of dopa to dopaquinone, and that peroxidase accomplishes the oxidative polymerization of the eventually formed indoles to eumelanin pigments. Dihydroxyphenylalanine 105-109 tyrosinase Homo sapiens 33-43 11744399-5 2001 This is consistent with the dopa detected during melanogenesis catalysed by tyrosinase being formed indirectly by a combination of dopaquinone intramolecular reductive addition to form leucodopachrome (cyclodopa), followed by redox exchange between remaining dopaquinone and leucodopachrome. Dihydroxyphenylalanine 28-32 tyrosinase Homo sapiens 76-86 11780467-2 2001 METHODS: Tyrosinase activity was estimated by measuring the rate of oxidation of DL-dopa. Dihydroxyphenylalanine 81-88 tyrosinase Homo sapiens 9-19 11124258-0 2001 Proper folding and endoplasmic reticulum to golgi transport of tyrosinase are induced by its substrates, DOPA and tyrosine. Dihydroxyphenylalanine 105-109 tyrosinase Homo sapiens 63-73 11124258-3 2001 Here, we demonstrate that the substrates DOPA and tyrosine induced in melanoma cells a transition of misfolded wild type tyrosinase to the native form that is resistant to proteolysis, competent to exit the endoplasmic reticulum, and able to produce melanin. Dihydroxyphenylalanine 41-45 tyrosinase Homo sapiens 121-131 11124258-4 2001 Because the enzymatic activity of tyrosinase is induced by DOPA, we propose that proper folding of the wild type protein, just like mutant forms, is tightly linked to its catalytic state. Dihydroxyphenylalanine 59-63 tyrosinase Homo sapiens 34-44 11124258-5 2001 Loss of pigmentation, therefore, in tyrosinase-positive melanoma cells is a consequence of tumor-induced metabolic changes that suppress tyrosinase activity and DOPA production within these cells. Dihydroxyphenylalanine 161-165 tyrosinase Homo sapiens 36-46 11118690-5 2001 Finally, the capacity of tyrosinase immobilization onto swollen beads was about 14 times greater than chitosan flakes, which was reflected by the higher yield of 3,4-dihydroxyphenylalanine from tyrosine and ascorbic acid in the heterogeneous catalytic system. Dihydroxyphenylalanine 162-188 tyrosinase Homo sapiens 25-35 11404842-0 2001 Melanogenesis by tyrosinase action on 3,4-dihydroxyphenylalanine (DOPA) in the presence of polyethylene glycol: a matrix-assisted laser desorption/ionization mass spectrometric investigation. Dihydroxyphenylalanine 38-64 tyrosinase Homo sapiens 17-27 11404842-0 2001 Melanogenesis by tyrosinase action on 3,4-dihydroxyphenylalanine (DOPA) in the presence of polyethylene glycol: a matrix-assisted laser desorption/ionization mass spectrometric investigation. Dihydroxyphenylalanine 66-70 tyrosinase Homo sapiens 17-27 11404842-6 2001 The results show that, in the presence of PEG, tyrosinase-catalyzed oligomerization of DOPA exhibits kinetics slower than those observed in the absence of the polymer. Dihydroxyphenylalanine 87-91 tyrosinase Homo sapiens 47-57