Studies of the Vitamin K-Dependent Carboxylase and Vitamin K Epoxide Reductase in Rat Liver
作者:
J.W. Suttie,
P.C. Preusch,
期刊:
Pathophysiology of Haemostasis and Thrombosis
(Karger Available online 1986)
卷期:
Volume 16,
issue 3-4
页码: 193-215
ISSN:1424-8832
年代: 1986
DOI:10.1159/000215293
出版商: S. Karger AG
关键词: Vitamin K;Prothrombin;Anticoagulants;Warfarin;γ-Carboxyglutamic acid
数据来源: Karger
摘要:
Vitamin K is required as a cofactor for a microsomal enzyme that converts glutamyl residues in precursor proteins to γ-carboxyglutamyl residues in completed proteins. These residues are essential for the biological function of prothrombin, factors VII, IX, and X, protein C, and protein S. Current data suggest that recognition of protein substrates by the carboxylase requires an unidentified protein-protein interaction in addition to the Glu substrate binding site. The primary vitamin K-dependent event has now been shown to be the abstraction of the γ-hydrogen of the substrate Glu residue with the concurrent formation of vitamin K 2,3-epoxide. Coumarin anticoagulants appear to inhibit the microsomal vitamin K epoxide reductase and one of a number of microsomal quinone reductases. They therefore block vitamin K action by preventing the recycling of vitamin K epoxide to the quinone and to the active cofactor form, the hydroquinone. Excess vitamin K can reverse a coumarin anticoagulant effect as the nonsensitive quinone reductase can continue to furnish the active coenzym
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