Isoenzymes of vitamin-K-dependent carboxylase

Vitamin-K-dependent carboxylase was prepared from bovine liver, kidney, lung and testis and it was checked that these systems obeyed the laws of normal enzyme kinetics. Four carboxylatable substrates were obtained from different sources and the apparent Michaelis constants of the various carboxylases for these four substrates were measured. From the results thus obtained we concluded that carboxylase is a group name for a number of isoenzymes which are present in hepatic as well as in various non-hepatic tissues.