Solubilization of protein BM-40 from a basement membrane tumor with chelating agents and evidence for its identity with osteonectin and SPARC.

Up to 80% of the calcium-binding protein BM-40 could be extracted from a tumor basement membrane with a physiological buffer containing 10 mM EDTA. About half of its amino acid sequence was determined by Edman degradation demonstrating identity with cDNA deduced sequences of bone osteonectin and SPARC.