Purification and partial characterization of a Mr 52,000 glycoprotein from human cancer ascites fluid which stimulates bone resorption in vitro.
A glycoprotein which stimulates bone resorption in vitro has been purified at least 375-fold from human cancer ascites fluid. Purification was accomplished utilizing fractionation with ammonium sulfate, anion exchange chromatography, high-performance size exclusion chromatography, adsorptive chromatography on hydroxylapatite, and high-performance anion exchange chromatography. The homogeneous bone-resorptive protein possesses an apparent molecular weight of 52,000 as calculated from electrophoresis in sodium dodecyl sulfate:polyacrylamide gels. On polyacrylamide gels at pH 8.9 in the absence of sodium dodecyl sulfate, the bone-resorptive protein migrates with the mobility of an alpha 2-globulin. The amino acid composition of this protein is marked by the absence of methionine and by a relatively high content of nonpolar amino acids. The protein possesses a single amino- and a single carboxyl-terminal amino acid, alanine, and leucine, respectively. The carbohydrate moiety, comprising 20% of the total weight, consists of neutral hexoses, galactosamine and glucosamine, and sialic acids. With respect to its biological activity, the ascites glycoprotein is one-fourth as potent as parathyroid hormone, on a molar basis, in its ability to stimulate calcium release from bone explants in vitro. Calcium release is significantly decreased on heating at 60 degrees C but is not inhibited by indomethacin.
D000328:Adult; D001202:Ascitic Fluid / Q000503:physiopathology*; D001688:Biological Products / Q000302:isolation & purification*; D001862:Bone Resorption; D001943:Breast Neoplasms / Q000032:analysis*; D016207:Cytokines; D005260:Female; D006023:Glycoproteins / Q000302:isolation & purification* / Q000502:physiology; D006801:Humans; D008970:Molecular Weight; D009363:Neoplasm Proteins / Q000302:isolation & purification*
D001688:Biological Products; D016207:Cytokines; D006023:Glycoproteins; D009363:Neoplasm Proteins; C025940:bone resorption factor