title: Relation between structure and function in some partially synthetic ribonucleases S'. Enzymic and spectroscopic investigation on [Orn10, Asn14]-RNase S' and 1epsilon, 7epsilon, 10delta-triguanidino-[Orn10, Asn14]-RNase S'.
abstract: Some analogues have been prepared of S-peptide, the peptide obtained together with S-protein from subtilisn-modified beef pancreatic R Nase A. The syntheses are described of [Orn10, Asn14]-S-peptide and 1epsilon, 7epsilon, 10delta-triguanidino-[Orn10, Asn14]-S-peptide. The S-peptide analogues are able to activate S-protein at the level of the parent [Orn10]-S-peptide and 1epsilon, 7epsilon-diguanidino-S-peptide respectively, although at high peptide-to-protein molar ratios. After their recombination with S-protein the buried character of Tyr-25 was restored, as judged from difference absorption and circular dichroism spectra in the near-ultraviolet region. These findings indicate that the asparaginyl residue is a possible naturally occurring substituent in the R Nase A sequences whose state of amidation in position 14 has not yet been defined.
mesh_terms: D000595:Amino Acid Sequence; D000596:Amino Acids / Q000032:analysis; D000818:Animals; D001215:Asparaginase; D001665:Binding Sites; D002417:Cattle; D002942:Circular Dichroism; D004789:Enzyme Activation; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D009904:Optical Rotation; D009952:Ornithine; D010179:Pancreas / Q000201:enzymology; D011485:Protein Binding; D011487:Protein Conformation; D012260:Ribonucleases / Q000378:metabolism; D013056:Spectrophotometry, Ultraviolet; D013329:Structure-Activity Relationship; D013381:Subtilisins
chemical_list: D000596:Amino Acids; D009952:Ornithine; D012260:Ribonucleases; D013381:Subtilisins; D001215:Asparaginase