Purification of an onco-fetal antigen from mammary carcinoma cells

Mammary carcinoma cell membranes were solubilized by a zwitterionic detergent, 3-(3-cholamidopropyl)-dimethyl-ammonio)-propanesulfonate (CHAPS). The solubilized membrane components were resolved by high pressure liquid chromatography (HPLC) using a styrogel protein column. One of the fractions was found to react specifically with anti-F9-antiserum in a solid-phase immunosorbent assay. Following recycling this fraction was purified to homogeneity and had an N-terminal amino acid residue of lysine. Its molecular weight was estimated to be 15,000 daltons. No comparable fraction could be detected in the solubilized membrane components of nonmalignant mammary tissue.