Biosynthesis of Prothrombin: Intracellular Localization of the Vitamin K-Dependent Carboxylase and the Sites
نویسندگان
چکیده
Prothrombin is a vitamin K-dependent blood coagulation protein that undergoes posttranslational y-carboxylation and propeptide cleavage during biosynthesis. The propeptide contains the y-carboxylation recognition site that directs y-carboxylation. To identify the intracellular sites of carboxylation and propeptide cleavage, we monitored the synthesis of prothrombin in Chinese hamster ovary cells stably transfected with the prothrombin cDNA by immunofluorescent staining. The vitamin K-dependent carboxylase was located in the endoplasmic reticulum and Golgi complex. Antibodies specific to prothrombin processing intermediates were used for immunocytolocalization. Anti-des-y-carboxyprothrombin antibodies stained only the endoplasmic reticulum whereas antiproprothrombin antibodies (specific
منابع مشابه
Biosynthesis of prothrombin: intracellular localization of the vitamin K-dependent carboxylase and the sites of gamma-carboxylation.
Prothrombin is a vitamin K-dependent blood coagulation protein that undergoes posttranslational gamma-carboxylation and propeptide cleavage during biosynthesis. The propeptide contains the gamma-carboxylation recognition site that directs gamma-carboxylation. To identify the intracellular sites of carboxylation and propeptide cleavage, we monitored the synthesis of prothrombin in Chinese hamste...
متن کاملPropeptide recognition by the vitamin K-dependent carboxylase in early processing of prothrombin and factor X.
Precursors of vitamin K-dependent proteins are synthesized with a propeptide that is believed to target these proteins for gamma-carboxylation by the vitamin K-dependent carboxylase. In this study synthetic propeptides were used to investigate gamma-carboxylation of the prothrombin and factor X precursors in rat liver microsomes. The extent of prothrombin processing by the carboxylase was also ...
متن کاملFunctional and Molecular Characterization of C91S Mutation in the Second Epidermal Growth Factor-like Domain of Factor VII
Background: Coagulation Factor VII is a vitamin K-dependent serine protease which has a pivotal role in the initiation of the coagulation cascade. The congenital Factor VII deficiency is a recessive hemorrhagic disorder that occurs due to mutations of F7 gene. In the present study C91S (p.C91S) substitution was detected in a patient with FVII deficiency. This mutation has not b...
متن کاملVitamin K - Dependent Biosynthesis of g - Carboxyglutamic Acid
VITAMIN K, AN ESSENTIAL vitamin, is a cofactor for a single known enzymatic reaction: the conversion of glutamic acid to g-carboxyglutamic acid in vitamin K-dependent proteins during their biosynthesis. Since the discovery of vitamin K and its association with blood coagulation,1 many milestones have been passed on the road to understanding the biological role of vitamin K. Important early land...
متن کاملAbnormal prothrombin in the plasma of rats carrying hepatic tumors.
Vitamin K is required for the posttranslational formation of gamma-carboxyglutamyl residues in a number of plasma clotting factors. Interference with vitamin K action results in the appearance of abnormal (des-gamma-carboxy) forms of prothrombin in human plasma. Vitamin K-sufficient patients with primary hepatocellular carcinoma also secrete significant quantities of abnormal prothrombin; this ...
متن کامل