THE MECHANISM OF ACTION OF VITAMIN K
- Authors
- Dowd, Paul; Ham, Seung-Wook; Naganathan, Sriram; Hershline, Roger
- Issue Date
- Jan-1995
- Publisher
- ANNUAL REVIEWS INC
- Keywords
- carboxylation; glutamate; γ-carboxyglutamate; blood clotting; coagulation; oxygenation
- Citation
- ANNUAL REVIEW OF NUTRITION, v.15, pp 419 - 440
- Pages
- 22
- Journal Title
- ANNUAL REVIEW OF NUTRITION
- Volume
- 15
- Start Page
- 419
- End Page
- 440
- URI
- https://scholarworks.bwise.kr/cau/handle/2019.sw.cau/55953
- ISSN
- 0199-9885
1545-4312
- Abstract
- Vitamin K is the blood-clotting vitamin. The mechanism of action of vitamin K is discussed in terms of a new carbanion model that mimics the proton abstraction from the gamma position of protein-bound glutamate. This is the essential step leading to carboxylation and activation of the blood-clotting proteins. The model comprises an oxygenation that is coupled to carbon-carbon bond formation, as is the oxygenation of vitamin K hydroquinone to vitamin K oxide. The model hypothesis is also supported by the mechanism of inhibition of the carboxylase by HCN, which acts as an acid-base inhibitor rather than a metal-complexing inhibitor. The new model postulates a dioxetane intermediate that explains the presence of a second atom of O-18 (from O-18(2)) incorporated into vitamin K oxide in the course of the enzymatic carboxylation. Finally, the chemistry developed here has been used to define the active site of vitamin K hydroquinone as the carbon-carbon bond adjacent to the methyl group.
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Collections - College of Natural Sciences > Department of Chemistry > 1. Journal Articles
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