Electron-spin resonance studies of bovine-serum albumin and cystine irradiated with gamma-rays at 77 degree K and at room temperature.

Abstract

SummaryPrevious investigations at room temperature have shown that irradiated proteins, in general, give rise to only two types of resonance pattern. One of these is asymmetric and similar to that of cystine. This similarity has led to the postulate that unpaired electrons formed within the protein migrate to the sulphur atoms of the cystine residue.We have found that the ESR spectrum obtained with BSA after irradiation in vacuum and examination at 77°k is different from that obtained on warming to room temperature. That observed on warming to room temperature is qualitatively the same as that obtained after irradiation in vacuum at room temperature, although the concentration of radicals in this latter case is greater.With cystine the ESR pattern obtained after irradiation in a vacuum and examination at 77°k is different from that obtained on warming to room temperature. This radical observed on warming to room temperature is very stable and is also produced after irradiation in vacuum at room temperatur...