ISOLATION AND CHARACTERIZATION OF AFP-BINDING PROTEINS FROM TUMOR ANDFETAL HUMAN TISSUES

The AFP receptor (rAFP) was discovered in embryonal and tumor tissues with a high level of proliferation. The AFP-binding protein (AFPbp) po ssibly containing the AFP-receptor (rAFP) was isolated from human embr yos and human breast cancer tissue using affinity chromatography on an AFP-Sepharose column. The similarity of molecular weight, subunit com position, and immunological characteristics was shown for embryonal an d tumor AFPbp using immunoblotting, gel-filtration, and PAAG electroph oresis. Judging from Superose-12 gel-filtration data, the protein mole cular weight made up to 320-380 kDa. The presence of an IgG-binding si te was detected in embryonal and tumor AFPbp by Western blot analysis.