Purification and characterization of B-protein from human serum.
B-Protein, present in the serum of individuals with cancer, has been purified to electrophoretic homogeneity. The purification procedure consisted of chromatography on Sephacryl S-200, Affi-Gel Blue, Con A--Sepharose 4B, wheat germ lectin--Sepharose and preparative polyacrylamide gel electrophoresis. The molecular weight of B-Protein is estimated to be 100 000 to 120 000. It is a glycoprotein which appears to be composed of two subunits, each with a molecular weight of approximately 52 000. Analytical polyacrylamide gel electrophoresis and analytical ultracentrifugation data indicate that purified B-Protein is homogeneous. Isoelectric focusing studies also show the purified B-Protein to be homogeneous in composition consisting of a single band of pI = 4.8. Amino acid analysis is consistent with this acidic isoelectric point. Other analyses indicate that B-Protein contains 7% carbohydrate and 7% lipid in the form of triglycerides.
D000596:Amino Acids / Q000032:analysis; D002850:Chromatography, Gel; D006023:Glycoproteins / Q000097:blood*; D006801:Humans; D007526:Isoelectric Point; D008970:Molecular Weight; D009363:Neoplasm Proteins / Q000097:blood*; D009369:Neoplasms / Q000097:blood*
D000596:Amino Acids; D006023:Glycoproteins; D009363:Neoplasm Proteins