Purification and partial characterization of a protein from cancer ascites fluid which stimulates the resorption of bone explants in vitro.
A protein capable of stimulating bone resorption in vitro has been purified approximately 1250-fold from cancer ascites fluid. Purification was accomplished employing successive fractionation with ammonium sulfate, ion exchange, and Cibacron blue affinity chromatography, isoelectric focusing, and selective adsorption on hydroxylapatite. The bone-resorptive protein obtained by this procedure appeared homogeneous in polyacrylamide gels at pH 9.5, migrating with the mobility of an alpha 2-globulin, and in sodium dodecyl sulfate polyacrylamide gels from which an apparent molecular weight of 43,000 was calculated. The amino acid composition of the bone-resorptive protein distinguished itself by the absence of methionine and by its relatively high content of glycine (17%) and proline (11%). Furthermore, the protein possesses a single NH2-terminal amino acid residue (glycine). The ascites protein was found to contain 19% carbohydrate by weight including a high content of sialic acid (15 residues/mol) as compared to the other sugars (27 residues/mol). As to its biological properties, the homogeneous ascites glycoprotein proved to be as potent as parathyroid hormone in its ability to stimulate bone resorption in vitro.
D000328:Adult; D000368:Aged; D000596:Amino Acids / Q000032:analysis; D000818:Animals; D000831:Animals, Newborn; D001201:Ascites / Q000503:physiopathology; D001681:Biological Assay; D001862:Bone Resorption / Q000187:drug effects*; D001842:Bone and Bones / Q000187:drug effects; D002241:Carbohydrates / Q000032:analysis; D005260:Female; D006801:Humans; D008297:Male; D051379:Mice; D008875:Middle Aged; D009363:Neoplasm Proteins / Q000302:isolation & purification* / Q000494:pharmacology; D009924:Organ Culture Techniques; D010534:Peritoneal Neoplasms / Q000503:physiopathology / Q000556:secondary*
D000596:Amino Acids; D002241:Carbohydrates; D009363:Neoplasm Proteins