Polyglutamyl derivatives of tetrahydrofolate as substrates for Lactobacillus casei thymidylate synthase.
Polyglutamyl derivatives of tetrahydrofolate as substrates for Lactobacillus casei thymidylate synthase.
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四氢叶酸的聚谷氨酰衍生物作为干酪乳杆菌胸苷酸合酶的底物。
DOI：
10.1021/bi00507a044
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发表时间：
1981
期刊：
影响因子：
2.9
通讯作者：
Montgomery,JA
中科院分区：
文献类型：
--
作者：
Kisliuk,RL;Gaumont,Y;Lafer,E;Baugh,CM;Montgomery,JA
Roy L.放大图片作者：Kisliuk，* Yvette Gaumont，Eileen Lafer，Charles M. Baugh，and John A.蒙哥马利摘要：四氢蝶酰聚谷氨酸含有多达7个Glu残基进行了测试，作为底物的乳杆菌-cilluscasei胸苷酸合酶。Km值从单谷氨酸的24 µ降至三谷氨酸的1.8 µ。添加残基4、5、6和7没有进一步降低Km。当monoglutamate和polyglutamate底物同时孵育的酶，所观察到的速率是特征的polyglutamate，即使当monoglutamate浓度是44倍的polyglutamate。碘乙酰胺处理抑制四氢叶酸（H4 PteGlu）1通常以聚（-谷氨酰）衍生物的形式存在于组织中（Baugh & Krumdieck，1971）。然而，大多数关于叶酸需要酶的研究使用H4 PteGU]作为底物，因为其容易获得。叶酸酶通常对聚谷氨酸的影响高于对H4 PteGlu的影响。（Baggott和Krumdieck，1979; Cheng等人，1975; Coward等人，1974; Curthoys & Rabinowitz，1972; Kisliuk等人，1974年;麦肯齐和鲍格，1980年;马修斯和鲍格，1980年）。鉴于胸苷酸合酶（5，10-亚甲基四氢叶酸：dUMP C-甲基转移酶，EC 2.1. 1.45）英寸
Roy L. Kisliuk,* Yvette Gaumont, Eileen Lafer, Charles M. Baugh, and John A. Montgomery abstract: Tetrahydropteroylpolyglutamates containing up to seven Glu residues were tested as substrates for Lactoba-cillus casei thymidylate synthase. The Km values decreased from 24 µ for the monoglutamate to 1.8 µ for the tri-glutamate. Addition of residues 4, 5, 6, and 7 did not decrease the Km further. When monoglutamate and polyglutamate substrates were simultaneously incubated with the enzyme, the rate observed was characteristic of the polyglutamate even when the monoglutamate concentration was 44 times that of the polyglutamate. Iodoacetamide treatment inhibited theTetrahydrofolic acid (H4PteGlu) 1 is commonly found in tissues in the form of poly (-glutamyl) derivatives (Baugh & Krumdieck, 1971). However, most studies on folate requiring enzymes employ H4PteGU] as substrate because of its ready availability. Folateenzymes generally show a higher afffmity for the polyglutamates than for H4PteGlu!(Baggott & Krumdieck, 1979; Cheng et al., 1975; Coward et al., 1974; Curthoys & Rabinowitz, 1972; Kisliuk et al., 1974; Mackenzie & Baugh, 1980; Matthews & Baugh, 1980). In view of the importance of thymidylate synthase (5, 10-methylenetetra-hydrofolate: dUMP C-methyltransferase, EC 2.1. 1.45) in