title: Vitamin K-dependent carboxylase: the carboxylation of exogenous substrates in different systems.
abstract: Two types of solid-phase carboxylase, SPC-II and SPC-X, have been prepared from the livers of warfarin-treated cows. Their enzymatic activities were compared with substrate-free carboxylase in microsomes from normal cows and substrate-bound carboxylase in microsomes from warfarin-treated cows. A number of exogenous substrates for carboxylase have been purified and tested. We found that large substrates, such as descarboxyprothrombin, are carboxylated only by substrate-free carboxylase and not by the substrate-bound enzyme. No differences in apparent Km values between solid-phase carboxylases II and X were observed.
mesh_terms: D000818:Animals; D015415:Biomarkers; D019735:Carbon-Carbon Ligases; D002417:Cattle; D005260:Female; D007700:Kinetics; D008025:Ligases / Q000378:metabolism*; D008862:Microsomes, Liver / Q000187:drug effects / Q000201:enzymology*; D011498:Protein Precursors; D011516:Prothrombin / Q000031:analogs & derivatives / Q000378:metabolism; D014859:Warfarin / Q000494:pharmacology
chemical_list: D015415:Biomarkers; D011498:Protein Precursors; C008208:acarboxyprothrombin; D014859:Warfarin; D011516:Prothrombin; D008025:Ligases; D019735:Carbon-Carbon Ligases; C020660:glutamyl carboxylase