title: Purification of a calcium binding protein (rat SPARC) from primary Sertoli cell-enriched culture medium.
abstract: A protein with an apparent Mr of 43,000 was purified from Sertoli cell-enriched culture medium by sequential anion-exchange, gel permeation, C4 reversed-phase, and diphenyl reversed-phase HPLC. N-Terminal sequence analysis of this protein revealed a sequence of NH2-XPQTEAAEEMVAEETVV for the first 17 amino acids. Comparison of this sequence with existing protein data base maintained at the Protein Identification Resource revealed that it shares extensive identity with a previously described protein secreted by mouse embryo parietal endoderm, SPARC, which is equivalent to a protein secreted by a basement-membrane-producing tumor, BM-40; and a bone protein, osteonectin. This protein also possesses similar in vitro biological activity of SPARC in which it binds Ca2+. The possible physiological significance of this protein was discussed.
authors.affiliation: Population Council, New York, New York 10021.
authors.forename: C Y
authors.initials: CY
authors.lastname: Cheng
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002135:Calcium-Binding Proteins / Q000302:isolation & purification*; D002478:Cells, Cultured; D002851:Chromatography, High Pressure Liquid; D002852:Chromatography, Ion Exchange; D003470:Culture Media; D004591:Electrophoresis, Polyacrylamide Gel; D008297:Male; D051379:Mice; D008969:Molecular Sequence Data; D015676:Osteonectin / Q000302:isolation & purification*; D051381:Rats; D012689:Sequence Homology, Nucleic Acid; D012708:Sertoli Cells / Q000378:metabolism*
chemical_list: D002135:Calcium-Binding Proteins; D003470:Culture Media; D015676:Osteonectin