Vitamin K-dependent carboxylase: synthesis of an inhibitor of the glutamyl binding site.

Liver microsomes contain a vitamin K and O2-dependent carboxylase that converts peptide-bound glutamyl residues to gamma-carboxyglutamate residues. The peptide Boc-O-phospho-Ser-O-phospho-Ser-Leu-OMe has now been synthesized. This peptide inhibits the carboxylation of endogenous protein precursors by a detergent-solubilized preparation of the carboxylase and is an apparent competitive inhibitor of the carboxylation of Phe-Leu-Glu-Glu-Leu.