Gamma-Carboxyglutamic Acid (gla)

Carboxyglutamic acid (or the conjugate base, carboxyglutamate) is an uncommon amino acid introduced into proteins by a post-translational carboxylation of glutamic acid residues. This modification is found, for example, in clotting factors and other proteins of the coagulation cascade.

This modification introduces an affinity for calcium ions. In the blood coagulation cascade, Vitamin K is required to introduce gamma-carboxylation of clotting factors II, VII, IX, and X. Gamma-glutamyl carboxylase is an enzyme which oxidizes Vitamin K hydroquinone to Vitamin K 2,3 epoxide, while simultaneously adding CO₂ to protein-bound glutamic acid (abbreviation = Glu) to form gamma-carboxyglutamic acid (also called gamma-carboxyglutamate, abbreviation = Gla).