This peptide is des-gamma-carboxylated osteocalcin/bone Gla protein (BGP). Osteocalcin/BGP is the most abundant non-collagenous protein of the bone extracellular matrix and is secreted by osteoblasts. This des-gamma-carboxylated peptide serves as a substrate for vitamin K-dependent carboxylase, which modifies Glu17, Glu21, and Glu24 to Gla residues.