Propeptide and glutamate-containing substrates bound to the vitamin K-dependent carboxylase convert its vitamin K epoxidase function from an inactive to an active state.
Propeptide and glutamate-containing substrates bound to the vitamin K-dependent carboxylase convert its vitamin K epoxidase function from an inactive to an active state.
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与维生素 K 依赖性羧化酶结合的前肽和含谷氨酸底物将其维生素 K 环氧化酶功能从非活性状态转变为活性状态。
DOI：
10.1073/pnas.94.17.9069
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发表时间：
1997
影响因子：
11.1
通讯作者：
Furie,BC
中科院分区：
文献类型：
--
作者：
Sugiura,I;Furie,B;Walsh,CT;Furie,BC
维生素K依赖性γ-谷氨酰羧化酶催化含有γ-羧化识别位点（γ-CRS）的前体蛋白中谷氨酸翻译后转化为γ-羧基谷氨酸。在此反应中，谷氨酸转化为γ-羧基谷氨酸，而维生素KH 2转化为维生素K 2，3-环氧化物。用一步免疫亲和法纯化了不含γ-CRS前肽和内源性底物的重组牛羧化酶。我们发现，在不存在含有γ-CRS的前肽和/或含有谷氨酸的底物的情况下，羧化酶几乎没有或没有环氧酶活性。环氧化酶活性由Phe-Leu-Glu-Glu-Leu（FLEEL）诱导（9.2 pmol/min/pmol酶），前肽，前因子IX的-18至-1残基（3.4pmol/min/pmol酶）、FLEEL和前肽（100 pmol/min/pmol酶）和proPT 28（HVFLAPQQARSLLQRVRANTFLEEVRK，人羧基凝血酶原的−18至+10残基），（每pmol酶每分钟5.3 pmol）。这些结果表明，在前肽或含谷氨酸的底物的情况下，维生素K的羧化酶的氧化不会发生。加入前肽或含谷氨酸的底物后，酶转化为活性环氧酶。这种调节机制防止在没有羧化底物的情况下产生高反应性维生素K中间体。
The vitamin K-dependent γ-glutamyl carboxylase catalyzes the posttranslational conversion of glutamic acid to γ-carboxyglutamic acid in precursor proteins containing the γ-carboxylation recognition site (γ-CRS). During this reaction, glutamic acid is converted to γ-carboxyglutamic acid while vitamin KH2is converted to vitamin K 2,3-epoxide. Recombinant bovine carboxylase was purified free of γ-CRS-containing propeptide and endogenous substrate in a single-step immunoaffinity procedure. We show that in the absence of γ-CRS-containing propeptide and/or glutamate-containing substrate, carboxylase has little or no epoxidase activity. Epoxidase activity is induced by Phe-Leu-Glu-Glu-Leu (FLEEL) (9.2 pmol per min per pmol of enzyme), propeptide, residues −18 to −1 of proFactor IX (3.4 pmol per min per pmol of enzyme), FLEEL and propeptide (100 pmol per min per pmol of enzyme), and proPT28 (HVFLAPQQARSLLQRVRRANTFLEEVRK, residues −18 to +10 of human acarboxy-proprothrombin), (5.3 pmol per min per pmol of enzyme). These results indicate that in the absence of propeptide or glutamate-containing substrate, oxygenation of vitamin K by the carboxylase does not occur. Upon addition of propeptide or glutamate-containing substrate, the enzyme is converted to an active epoxidase. This regulatory mechanism prevents the generation of a highly reactive vitamin K intermediate in the absence of a substrate for carboxylation.