Title: Vitamin K-dependent carboxylase: Purification of the rat liver microsomal enzyme
Abstract: Rat liver microsomes contain a vitamin K-dependent enzyme that carboxylates glutamyl residues of precursor proteins to γ-carboxyglutamyl residues in completed biologically active proteins. Utilizing the carboxylation of the peptide Phe-Leu-Glu-Glu-Leu as an assay, a stable 100- to 150-fold increase in specific activity of this enzyme has been achieved by the selective extraction of other proteins from the membrane. The resulting preparation has the same general properties as the microsomal enzyme but requires a higher concentration of vitamin K and lower concentration of substrate for maximum activity. Microsomal vitamin K-dependent dehydrogenase activity has been lost during the purification, as the preparation requires the reduced form of vitamin K for activity and is not active in the presence of vitamin K and NADH. Much of the apparent purification results from the removal of a protein inhibitor(s) of the enzyme present in the crude microsomal preparation. The resulting preparation appears to require lipid for maximum activity but no longer contains intact membranes.
Publication Year: 1980
Publication Date: 1980-07-01
Language: en
Type: article
Indexed In: ['crossref', 'pubmed']
Access and Citation
Cited By Count: 38
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