PMID-sentid Pub_year Sent_text comp_official_name comp_offsetprotein_name organism prot_offset 31667903-6 2020 In this article, we review the biochemical basis and scientific observations that suggest a significant interaction between N2 O and methotrexate due to their dual inhibition of the key enzyme methionine synthase. Nitrous Oxide 124-128 5-methyltetrahydrofolate-homocysteine methyltransferase Homo sapiens 193-212 3536916-0 1986 In vitro inactivation of methionine synthase by nitrous oxide. Nitrous Oxide 48-61 5-methyltetrahydrofolate-homocysteine methyltransferase Homo sapiens 25-44 3536916-2 1986 Prolonged exposure to N2O leads to megaloblastic anemia in humans and to loss of methionine synthase activity in vertebrates. Nitrous Oxide 22-25 5-methyltetrahydrofolate-homocysteine methyltransferase Homo sapiens 81-100 3536916-3 1986 We now report that purified preparations of cobalamin-dependent methionine synthase (5-methyltetrahydrofolate-homocysteine methyltransferase, EC 2.1.1.13) from both Escherichia coli and pig liver are irreversibly inactivated during turnover in buffers saturated with N2O. Nitrous Oxide 267-270 5-methyltetrahydrofolate-homocysteine methyltransferase Homo sapiens 64-83 3964518-0 1986 Effect of nitrous oxide on placental methionine synthase activity. Nitrous Oxide 10-23 5-methyltetrahydrofolate-homocysteine methyltransferase Homo sapiens 37-56 6631717-3 1983 Nitrous oxide treatment was used to inhibit the tetrahydrofolate-generating enzyme, 5-methyltetrahydrofolate homocysteine methyltransferase (methionine synthetase, E.C. Nitrous Oxide 0-13 5-methyltetrahydrofolate-homocysteine methyltransferase Homo sapiens 84-139 7306986-1 1981 5-Methyltetrahydrofolate homocysteine methyltransferase activity in human bone marrow cells obtained from patients undergoing surgical operation became low after about 4 hr of nitrous oxide (N2O) anesthesia. Nitrous Oxide 176-189 5-methyltetrahydrofolate-homocysteine methyltransferase Homo sapiens 0-55 7306986-1 1981 5-Methyltetrahydrofolate homocysteine methyltransferase activity in human bone marrow cells obtained from patients undergoing surgical operation became low after about 4 hr of nitrous oxide (N2O) anesthesia. Nitrous Oxide 191-194 5-methyltetrahydrofolate-homocysteine methyltransferase Homo sapiens 0-55 33642336-6 2021 In addition, N2O may mediate epigenetic changes by inhibiting methionine synthase, a key enzyme involved in DNA and RNA methylation. Nitrous Oxide 13-16 5-methyltetrahydrofolate-homocysteine methyltransferase Homo sapiens 62-81 3341574-0 1988 Rate of inactivation of human and rodent hepatic methionine synthase by nitrous oxide. Nitrous Oxide 72-85 5-methyltetrahydrofolate-homocysteine methyltransferase Homo sapiens 49-68 3964518-1 1986 Methionine synthase activity was measured in 11 placentae after Caesarean section during which nitrous oxide had been used as an anaesthetic agent, and compared with that from 20 placentae after normal vaginal delivery with no exposure to nitrous oxide. Nitrous Oxide 95-108 5-methyltetrahydrofolate-homocysteine methyltransferase Homo sapiens 0-19 32718428-6 2020 Nitrous oxide is known to inhibit methionine synthase, a vitamin B12-dependent enzyme responsible for the breakdown of homocysteine, resulting in homocysteine elevation, and should be avoided in these patients. Nitrous Oxide 0-13 5-methyltetrahydrofolate-homocysteine methyltransferase Homo sapiens 34-53 21680854-1 2011 BACKGROUND: Nitrous oxide inactivates vitamin B(12), inhibits methionine synthase, and consequently increases plasma total homocysteine (tHcy). Nitrous Oxide 12-25 5-methyltetrahydrofolate-homocysteine methyltransferase Homo sapiens 62-81 22584536-1 2012 BACKGROUND: Nitrous oxide converts vitamin B12 to its nonmetabolically active form, inhibits methionine synthase, and results in an elevation of plasma total homocysteine (tHcy). Nitrous Oxide 12-25 5-methyltetrahydrofolate-homocysteine methyltransferase Homo sapiens 93-112 22103938-5 2011 Biochemical alterations, in terms of homocysteine accumulation, demonstrated that intracellular methionine synthase had been inactivated by N(2)O absorbed by the cells, a process that also occurs in vivo. Nitrous Oxide 140-145 5-methyltetrahydrofolate-homocysteine methyltransferase Homo sapiens 96-115 19249419-2 2009 Many receive nitrous oxide, which impairs methionine synthase, thus inhibiting folate synthesis and increasing postoperative homocysteine levels. Nitrous Oxide 13-26 5-methyltetrahydrofolate-homocysteine methyltransferase Homo sapiens 42-61 19339913-1 2009 OBJECTIVES: Oxidation of vitamin B12 by nitrous oxide leads to the inactivation of methionine synthase resulting in elevated plasma total homocysteine concentrations. Nitrous Oxide 40-53 5-methyltetrahydrofolate-homocysteine methyltransferase Homo sapiens 83-102 19339913-11 2009 The average increase in plasma homocysteine was 2.4 mumol/l (+28%) in all three groups indicating the expected inactivation of methionine synthase by nitrous oxide through oxidation of vitamin B12, but no genetic effect. Nitrous Oxide 150-163 5-methyltetrahydrofolate-homocysteine methyltransferase Homo sapiens 127-146 10584542-2 1999 Nitrous oxide may cause neurological and haematological signs and symptoms, as a result of its tendency to form complex with cobalt(I) in methylcobalamin, the cofactor for methionine synthase (EC 2.1.1.13), resulting in irreversible oxidation of the cofactor and inactivation of the enzyme protein. Nitrous Oxide 0-13 5-methyltetrahydrofolate-homocysteine methyltransferase Homo sapiens 172-191 17404524-7 2007 CONCLUSIONS: The inactivation of methionine synthase and L methylmalonylcoA mutase by nitrous oxide has been previously demonstrated. Nitrous Oxide 86-99 5-methyltetrahydrofolate-homocysteine methyltransferase Homo sapiens 33-52 16182898-1 2005 BACKGROUND: Nitrous oxide inactivates vitamin B12 and methionine synthase, thereby impairing DNA formation and, consequently, new cell formation. Nitrous Oxide 12-25 5-methyltetrahydrofolate-homocysteine methyltransferase Homo sapiens 54-73 12751548-1 2003 Nitrous oxide interacts with vitamin B12 resulting in selective inhibition of methionine synthase, a key enzyme in methionine and folate metabolism. Nitrous Oxide 0-13 5-methyltetrahydrofolate-homocysteine methyltransferase Homo sapiens 78-97 16465233-3 1997 Using nitrous oxide to inactivate vitamin B12 we show that, in a variety of cell lines in vitro, methionine synthase is rapidly inhibited, the cells cease proliferation and undergo apoptosis. Nitrous Oxide 6-19 5-methyltetrahydrofolate-homocysteine methyltransferase Homo sapiens 97-116 10377254-0 1999 Co-ordinate variations in methylmalonyl-CoA mutase and methionine synthase, and the cobalamin cofactors in human glioma cells during nitrous oxide exposure and the subsequent recovery phase. Nitrous Oxide 133-146 5-methyltetrahydrofolate-homocysteine methyltransferase Homo sapiens 55-74 9219837-0 1997 Response of the methionine synthase system to short-term culture with homocysteine and nitrous oxide and its relation to methionine dependence. Nitrous Oxide 87-100 5-methyltetrahydrofolate-homocysteine methyltransferase Homo sapiens 16-35 7558184-1 1995 Inactivation of methionine synthase (MS) by nitrous oxide (N2O) administration to animals and man has been postulated to be mediated by hydroxyl radical (OH). Nitrous Oxide 44-57 5-methyltetrahydrofolate-homocysteine methyltransferase Homo sapiens 16-35 7573909-2 1995 Nitrous oxide (N2O) oxidises vitamin B12 and thus decreases DNA production by inactivation of methionine synthase. Nitrous Oxide 0-13 5-methyltetrahydrofolate-homocysteine methyltransferase Homo sapiens 94-113 7573909-2 1995 Nitrous oxide (N2O) oxidises vitamin B12 and thus decreases DNA production by inactivation of methionine synthase. Nitrous Oxide 15-18 5-methyltetrahydrofolate-homocysteine methyltransferase Homo sapiens 94-113 7558184-1 1995 Inactivation of methionine synthase (MS) by nitrous oxide (N2O) administration to animals and man has been postulated to be mediated by hydroxyl radical (OH). Nitrous Oxide 59-62 5-methyltetrahydrofolate-homocysteine methyltransferase Homo sapiens 16-35 7719049-2 1995 Nitrous oxide (N2O) oxidizes vitamin B12 and thus decreases DNA production by inactivation of methionine synthase. Nitrous Oxide 0-13 5-methyltetrahydrofolate-homocysteine methyltransferase Homo sapiens 94-113 7719049-2 1995 Nitrous oxide (N2O) oxidizes vitamin B12 and thus decreases DNA production by inactivation of methionine synthase. Nitrous Oxide 15-18 5-methyltetrahydrofolate-homocysteine methyltransferase Homo sapiens 94-113 8142373-0 1994 Nitrous oxide degradation by cobalamin-dependent methionine synthase: characterization of the reactants and products in the inactivation reaction. Nitrous Oxide 0-13 5-methyltetrahydrofolate-homocysteine methyltransferase Homo sapiens 29-68 8017644-0 1994 Preoperative methionine loading enhances restoration of the cobalamin-dependent enzyme methionine synthase after nitrous oxide anesthesia. Nitrous Oxide 113-126 5-methyltetrahydrofolate-homocysteine methyltransferase Homo sapiens 87-106 8017644-3 1994 The inactivation of methionine synthase by nitrous oxide in cultured human fibroblasts is decreased at high concentrations of methionine in culture medium. Nitrous Oxide 43-56 5-methyltetrahydrofolate-homocysteine methyltransferase Homo sapiens 20-39 8017644-7 1994 RESULTS: After nitrous oxide exposure, a considerable inactivation of methionine synthase in mononuclear white blood cells was seen in all patients, reaching a nadir after 5-48 h. In the patients not subjected to a methionine load, recovery of enzyme activity was not complete within 7 days. Nitrous Oxide 15-28 5-methyltetrahydrofolate-homocysteine methyltransferase Homo sapiens 70-89 8017644-12 1994 CONCLUSIONS: Our data suggest that short time exposure to nitrous oxide selectively impairs the function of the cobalamin-dependent methionine synthase. Nitrous Oxide 58-71 5-methyltetrahydrofolate-homocysteine methyltransferase Homo sapiens 112-151 1637609-0 1992 Influence of vitamin B12 status on the inactivation of methionine synthase by nitrous oxide. Nitrous Oxide 78-91 5-methyltetrahydrofolate-homocysteine methyltransferase Homo sapiens 55-74 8134195-1 1994 We investigated the nitrous oxide-induced inactivation of methionine synthase and the concurrent homocysteine (Hcy) export in mutant fibroblasts with defects in the homocysteine catabolizing enzyme, cystathionine beta-synthase, or in methionine synthase, which carries out homocysteine remethylation. Nitrous Oxide 20-33 5-methyltetrahydrofolate-homocysteine methyltransferase Homo sapiens 58-77 8134195-1 1994 We investigated the nitrous oxide-induced inactivation of methionine synthase and the concurrent homocysteine (Hcy) export in mutant fibroblasts with defects in the homocysteine catabolizing enzyme, cystathionine beta-synthase, or in methionine synthase, which carries out homocysteine remethylation. Nitrous Oxide 20-33 5-methyltetrahydrofolate-homocysteine methyltransferase Homo sapiens 234-253 8134195-10 1994 The low susceptibility of methionine synthase to nitrous oxide in the presence of high methionine or in cb1G or cb1E mutants is probably related to low catalytic turnover. Nitrous Oxide 49-62 5-methyltetrahydrofolate-homocysteine methyltransferase Homo sapiens 26-45 8263793-0 1993 Methionine synthase inactivation by nitrous oxide during methionine loading of normal human fibroblasts. Nitrous Oxide 36-49 5-methyltetrahydrofolate-homocysteine methyltransferase Homo sapiens 0-19 8263793-2 1993 Nitrous oxide inactivates the enzyme methionine synthase by oxidation of enzyme bound cobalamin, which is formed from the cofactor methylcobalamin during the catalytic cycle. Nitrous Oxide 0-13 5-methyltetrahydrofolate-homocysteine methyltransferase Homo sapiens 37-56 1637609-1 1992 We have studied the influence of maternal serum B12 concentration on the inactivation of placental methionine synthase activity by nitrous oxide in an obstetric population. Nitrous Oxide 131-144 5-methyltetrahydrofolate-homocysteine methyltransferase Homo sapiens 99-118 1637609-4 1992 There was a highly significant relation between placental methionine synthase activity and duration of exposure to nitrous oxide. Nitrous Oxide 115-128 5-methyltetrahydrofolate-homocysteine methyltransferase Homo sapiens 58-77 1602376-1 1992 Nitrous oxide irreversibly inactivates cob(I)alamin, which serves as a cofactor of the enzyme methionine synthase catalyzing the remethylation of homocysteine to methionine. Nitrous Oxide 0-13 5-methyltetrahydrofolate-homocysteine methyltransferase Homo sapiens 94-113 1602376-11 1992 The enhancement of homocysteine export rate of some cell types during nitrous oxide exposure probably reflects inhibition of homocysteine remethylation in intact cells, and highlights the utility of extracellular homocysteine as an indicator of metabolic flux through the methionine synthase pathway. Nitrous Oxide 70-83 5-methyltetrahydrofolate-homocysteine methyltransferase Homo sapiens 272-291 2189194-1 1990 The administration of nitrous oxide rapidly inactivates the vitamin B12-dependent enzyme methionine synthase. Nitrous Oxide 22-35 5-methyltetrahydrofolate-homocysteine methyltransferase Homo sapiens 89-108 1809046-5 1991 Nitrous oxide reacts with the reduced form of vitamin B12, thereby inhibiting the action of methionine synthase, an enzyme that indirectly supports methylation reactions and nucleic acid synthesis. Nitrous Oxide 0-13 5-methyltetrahydrofolate-homocysteine methyltransferase Homo sapiens 92-111 2016907-1 1991 The effects of methotrexate (inhibiting dihydrofolate reductase) and nitrous oxide (inactivating methionine synthase) on intracellular folate coenzyme levels of leukemic cells were studied. Nitrous Oxide 69-82 5-methyltetrahydrofolate-homocysteine methyltransferase Homo sapiens 97-116 2407589-2 1990 Insufficient availability of cobalamin, or inhibition of methionine synthase by exposure to nitrous oxide, leads to diminished activity of this enzyme. Nitrous Oxide 92-105 5-methyltetrahydrofolate-homocysteine methyltransferase Homo sapiens 57-76