title: [Purification and activity evaluation of methionine synthase].
abstract: Methionine synthase (MS, EC2.1.1.13), a key enzyme in the folate metabolism area catalyzing methyl transfer from N5-methyltetrahydrofolate to homocysteine to give tetrahydrofolate and methionine, takes a core position in folate cycle, one-carbon-unit transfer and sculpture amino acid pathways. Cobalamin-dependent methionine synthase was purified from rat liver. The enzyme was purified 609-fold to near homogeneity by batch chromatography on DE-52, anion-exchange chromatography on Q Sepharose Fast Flow and CHT-I hydroxyapatite column and was identified by SDS-PAGE and Western blotting. The enzyme activity was determined by spectrophotometric assay. In addition, the influencing factor and optimal reaction condition were performed. The steady state kinetic of rat liver methionine synthase was similar to that of other mammalian cobalamin-dependent methionine synthase which employed a Ping-Pong mechanism. The result indicated that cobalamin-dependent methionine synthase purified from rat liver is suitable for screening and studying methionine synthase specific inhibitors.
authors: Department of Chemical Biology, School of Pharmaceutical Science, State Key Laboratory of Natural and Biomimetic Drugs, Peking University, Beijing 100083, China.
authors: Ying
authors: Y
authors: Guo
authors: Chao
authors: C
authors: Li
authors: Zhi-Li
authors: ZL
authors: Zhang
authors: Chao
authors: C
authors: Tian
authors: Xiao-Wei
authors: XW
authors: Wang
authors: Jun-Yi
authors: JY
authors: Liu
mesh_terms: D013766:5-Methyltetrahydrofolate-Homocysteine S-Methyltransferase / Q000302:isolation & purification* / Q000378:metabolism*; D000818:Animals; D004591:Electrophoresis, Polyacrylamide Gel; D005493:Folic Acid Antagonists / Q000494:pharmacology; D008099:Liver / Q000737:chemistry*; D008297:Male; D008727:Methotrexate / Q000494:pharmacology*; D011799:Quinazolines / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D013763:Tetrahydrofolates / Q000378:metabolism; D013876:Thiophenes / Q000494:pharmacology*
chemical_list: D005493:Folic Acid Antagonists; D011799:Quinazolines; D013763:Tetrahydrofolates; D013876:Thiophenes; D013766:5-Methyltetrahydrofolate-Homocysteine S-Methyltransferase; C068874:raltitrexed; C005984:5-methyltetrahydrofolate; D008727:Methotrexate