Osteonectin purified from human platelets. Acidic, Ca2+-binding glycoprotein found in a variety of embryonic and adult tissues containing actively proliferating and remodeling cells. Differs from the bone-derived osteonectin in its glycosylation pattern and its collagen binding specificity.
Secreted Protein Acidic & Rich in Cysteine Human Recombinant produced in E.Coli is a single, non- glycosylated polypeptide chain containing 286 amino acids and having a molecular mass of 32.7kDa.
SPARC is purified by proprietary chromatographic techniques.
SPARC, an acronym for “secreted protein, acidic and rich in cysteine”, is also known as osteonectin or BM-40. It is the founding member of a family of secreted matricellular proteins with similar domain structure. The 303 amino acid, 43 kDa protein contains a 17 aa signal sequence, an N-terminal acidic region that binds calcium, a follistatin domain containing Kazal-like sequences, and a C-terminal extracellular calcium (EC) binding domain with two EF-hand motifs. SPARC is produced by fibroblasts, capillary endothelial cells, platelets and macrophages, especially in areas of tissue morphogenesis and remodeling. SPARC shows context-specific effects, but generally inhibits adhesion, spreading and proliferation, and promotes collagen matrix formation. For endothelial cells, SPARC disrupts focal adhesions and binds and sequesters PDGF and VEGF. SPARC is abundantly expressed in bone, where it promotes osteoblast differentiation and inhibits adipogenesis.
