Osteocrin is a recently identified secreted protein expression of which was only detected in bone, peaking just after birth and decreasing markedly with age. A 1280-bp mRNA encodes osteocrin producing a mature protein of 103 amino acids with a molecular mass of 11.4kD. In primary osteoblastic cell cultures osteocrin expression coincided with matrix formation then decreased in very mature cultures. Treatment of cultures with 1,25-dihydroxyvitamin D3 resulted in a rapid dose dependent down-regulation of osteocrin expression, suggesting direct regulation. Chronic treatment of primary cultures with osteocrin-conditioned media inhibited mineralization and reduced osteocalcin and alkaline phosphatase expression. These results suggest that osteocrin represents a novel, unique vitamin D-regulated bone-specific protein that appears to act as a soluble osteoblast regulator. Recombinant human Osteocrin is fused with a N-terminal His-Tag. The Human Osteocrin His-Tagged Fusion Protein is 13.6kD containing 106 amino acid residues of the human Osteocrin and 16 additional amino acid residues Amino Acid Sequence: MRGSHHHHHH GMASHMVDVT TTEAFDSGVI DVQSTPTVRE EKSATDLTAK LLLLDELVSL ENDVIETKKK RSFSGFGSPL DRLSAGSVDH KGKQRKVVDH PKRRFGIPMD RIGRNRLSNS RG. Storage and Stability: Lyophilized and reconstituted products are stable for 6 months after receipt at -20C. Reconstitute with sterile acetate buffer. Aliquot to avoid repeated freezing and thawing. Store at -20C. For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap. Further dilutions can be made in assay buffer.
