Isolation of the transferrin receptor from human placenta.

The transferrin receptor (TFR) has been detected in tissues characterised by a high degree of proliferation. We have developed a procedure for isolating TFR from human placental tissues by affinity chromatography on transferrin-Sepharose. Using gel filtration and electrophoresis in 7% PAAG, it has been shown that the molecular mass of the protein is 180 kDa.

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.

Formation and properties of S-protein complex with S-peptide-containing fusion protein.

A fusion protein (FP) comprised of the RNase A S-peptide and human epidermal growth factor was shown to form a stable noncovalent catalytically active complex with the RNase A S-protein at a stoichiometric ratio 1:1 with Kdiss = 5.0 x 10(-7) M. The S-protein complex with FP exhibits the pyrimidine specificity toward substrates in both reactions catalyzed by RNase S, transesterification and hydrolysis.