A circular dichroic spectral study on disulfide-reduced pancreatic ribonuclease A and its renaturation to the active enzyme.
Disulfide-reduced RNase A, which could be reoxidized to give the native enzyme, was shown to have a CD spectrum quite different from that of the native enzyme or a random coil. Disulfide-reduced and fully cysteine-S-carboxamidomethylated RNase A because the derivative was stable and gave a spectrum identical to that of reduced RNase A. Curve-fitting analyses showed the presence of 14% alpha-helix and 25% beta-structure in this open chain derivative of RNase A. The time dependence of CD spectra during the oxidative renaturation of reduced RNase A was analyzed and changes in alpha-helical and beta-structure contents during the reaction were estimated. It was shown that the change in the content of beta-structure was slower than that of alpha-helix content and approximately paralleled the appearance of the enzymatic activity.
D000596:Amino Acids / Q000032:analysis; D002942:Circular Dichroism; D004220:Disulfides; D007460:Iodoacetamide / Q000494:pharmacology; D007700:Kinetics; D010179:Pancreas / Q000201:enzymology*; D011487:Protein Conformation; D012260:Ribonucleases / Q000378:metabolism
D000596:Amino Acids; D004220:Disulfides; D012260:Ribonucleases; D007460:Iodoacetamide