The Mode of Action of Vitamin K

TLDR

An unusual tryptic peptide from prothrombin contains part of the vitamin K‑dependent region, and its glutamic acid is γ‑carboxylated, indicating vitamin K dependence. A modified glutamylserine dipeptide was isolated from proteolytic digests of the vitamin K‑dependent peptide and characterized. Published in Nature Academy of Sciences, USA, 1973, 70:3366–3370.

Abstract

Abstract An unusual tryptic peptide isolated from the protein, prothrombin, has recently been shown to contain at least a portion of the vitamin K-dependent region of this protein (Nelsestuen, G. L., and Suttie, J. W. (1973) Proc. Nat. Acad. Sci. U. S. A. 70, 3366–3370). A modified glutamylserine dipeptide has been isolated from proteolytic digests of this vitamin K-dependent peptide and has been characterized. It has been unambiguously demonstrated that the glutamic acid of the glutamylserine has been substituted by carboxylation of the γ carbon atom so that the dipeptide structure is: [see PDF for equation] Presumably, the incorporation of the second γ-carboxyl group is dependent on vitamin K.