Purification, physicochemical characterization, and antitumor activity of a cancer-associated human serum protein that is increased by treatment with schizophyllan, an antitumor polysaccharide.
A serum protein was purified from normal human sera by several steps of purification, and tentatively designated as cancer-associated serum protein (CAP-135), since the content of the protein was remarkably decreased in cancer patients. The purified CAP-135 has an approximate molecular weight of 135,000 daltons, and is composed of three subunits of 78,000, 34,500 and 24,800 daltons. CAP-135 showed an isoelectric point of pH 5.5-5.8 and contained a small amount (1.38%) of neutral sugar. CAP-135 is assumed to be modified complement C3 on the basis that it reacted only with anticomplement C3 in immunodiffusion assay, and one of its subunits had a molecular weight similar to that of the beta-chain of human complement C3. The ip injection of CAP-135 apparently inhibited the growth of sarcoma-180 implanted into the groin of Jc1:ICR female mice. The present results indicate that CAP-135 may be of diagnostic value.
D000596:Amino Acids / Q000032:analysis; D000818:Animals; D003176:Complement C3 / Q000378:metabolism; D005260:Female; D006801:Humans; D007526:Isoelectric Point; D051379:Mice; D008815:Mice, Inbred Strains; D008970:Molecular Weight; D009363:Neoplasm Proteins / Q000302:isolation & purification*; D012510:Sarcoma 180 / Q000188:drug therapy; D012566:Sizofiran / Q000494:pharmacology
D000596:Amino Acids; D003176:Complement C3; D009363:Neoplasm Proteins; C040044:neoplasm-associated factor; D012566:Sizofiran