Isolation and characterization of AFP-binding proteins from tumor and fetal human tissues

The AFP receptor (rAFP) was discovered in embryonal and tumor tissues with a high level of proliferation. The AFP-binding protein (AFPbp) possibly containing the AFP-receptor (rAFP) was isolated from human embryos and human breast cancer tissue using affinity chromatography on an AFP-Sepharose column. The similarity of molecular weight, subunit composition, and immunological characteristics was shown for embryonal and tumor AFPbp using immunoblotting, gel-filtration, and PAAG electrophoresis. Judging from Superose-12 gel-filtration data, the protein molecular weight made up to 320-380 kDa. The presence of an IgG-binding site was detected in embryonal and tumor AFPbp by Western blot analysis.