Identification of Placental Transforming Growth Factor- and Bikunin Metabolites as

A contaminant protein complex found in pharmaceutical urinary human chorionic gonadotrophin preparations is reported to have anti-human immunodeficiency virus-as-sociated Kaposi’s sarcoma activity. The aim of this study was to isolate and characterize this protein com-plex by proteomic approaches. Size exclusion chroma-tography was used in the isolation of these human cho-rionic gonadotrophin-associated fragments. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed the presence of a protein complex that disso-ciated into two protein bands under reducing condi-tions. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry of this complex showed three polypeptides at 6.2, 11.4, and 15.8 kDa. Peptide mass mapping and N-terminal amino acid sequencin