Dioxygen and the vitamin K-dependent synthesis of prothrombin.
Ciba Found Symp, 1978/6-1978/6;(65):187-97.
Esnouf MP, Green MR, Hill HA, Irvine GB, Walter SJ
PMID: 225139
Abstract
It has been shown that bovine erythrocyte superoxide dismutase inhibits the gamma-carboxylation of glutamyl residues in the precursor of prothrombin and in a related synthetic peptide by a vitamin K-dependent rat liver microsomal carboxylase. In the same conditions a simple copper(II) tyrosinyl complex also inhibits the carobxylation. The formation of the vitamin K epoxide by the same systems is inhibited by both superoxide dismutase and catalase. It is suggested that the formation of the epoxide is a process distinct from carboxylation, representing perhaps a protective mechanism against the superoxide ion, or species derived therefrom, generated by the reaction of reduced vitamin K with dioxygen. Furthermore, the possibility that the carboxylating species is formed by the reaction of the superoxide ion, or species derived therefrom, with carbon dioxide, is proposed.
MeSH terms
Animals; Catalase; Epoxy Compounds; Microsomes, Liver; Oxidation-Reduction; Oxygen; Peroxides; Prothrombin; Rats; Superoxide Dismutase; Superoxides; Vitamin K
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