[Formation and properties of S-protein complexes with S-peptide-containing hybrid polypeptides]

The fused polypeptides of human epidermal growth factor and one or two S-peptide of RNase A was shown to form stoichiometric (1:1) strong noncovalent and enzymatically active complexes with S-protein of RNase A. The dissociation constants for these complexes were found to be 5.0 x 10(-7) M and 1.1 x 10(-7) M. The complexes of polypeptides with S-protein were capable to hydrolyze ribopolynucleotides, and pyrimidine-2',3'-cyclophosphates specifically, like RNase S'. A possibility was shown of effective purification of the S-peptide-containing polypeptides by affinity chromatography in which S-protein is immobilized on solid supports.