Vitamin K-dependent gamma-carboxyglutamic acid formation by mouse renal adenocarcinoma cells (RAG)

Previous studies have identified gamma-carboxyglutamic acid as a constituent of one or more protein(s) synthesized by rat and chicken kidney microsomes in vitro in a vitamin K-dependent post-translational reaction [1]. Incubation of microsomes from a mouse kidney cell line (RAG) with [14C]NaHCO3 results in formation of protein-bound [14C]gamma-carboxylglutamic acid. Incorporation is stimulated threefold by addition of the active vitamin K compound 2-methyl, 3-farnesyl, 1,4-naphthoquinone. At least 90% of incorporated, nondialyzable [14C] is situated in the gamma-carboxyl group of gamma-carboxyglutamic acid residues.