Characterization of the complex between bovine osteocalcin and type I collagen.

This study examined the association of bovine osteocalcin with type I collagen under a variety of conditions, including different buffers, pH, and concentrations of phosphate and Ca(II). The data showed that osteocalcin binds to type I collagen reversibly with a binding constant which varies from 4000 to 160,000 M(-1), depending upon the exact conditions. Furthermore, the results indicated that there is only one osteocalcin binding site per collagen molecule. The absence or presence of Ca(II) and/or phosphate in the buffer had little effect on complex formation.