MECHANISM OF GLUTATHIONE REGENERATION OF REDUCED PANCREATIC RIBONUCLEASE A

A comparative study was made of the kinetics of glutathione regeneration of reduced pancreatic ribonuclease A, as determined by circular dichroism, sulfhydryl oxidation and the kinetics of reactivation. Four sulfhydryls were reoxidized prior to any large circular dichroic changes or recovery of enzymatic activity. The helical and β segments in ribonuclease were shown to reform at approximately the same rate. The results are discussed in terms of a regeneration mechanism for ribonuclease involving (1) nucleation, (2) polypeptide backbone refolding, and (3) reshuffling of incorrectly paired disulfide bonds.