γ-Radiolysis of disulfides in aqueous solution. III. L-Cysteine-D-penicillamine mixed disulfide

• Published in: Canadian journal of chemistry Vol. 47; no. 6; pp. 1037 - 1043
• Main Author: Purdie, J. W
• Format: Journal Article
• Language: English
• Published: Ottawa, Canada NRC Research Press 15.03.1969
• ISSN: 0008-4042; 1480-3291
• DOI: 10.1139/v69-163

L -Cysteine- D -penicillamine mixed disulfide (CySSPen) was irradiated in aerated and deaerated aqueous solutions with 60 Co γ-rays. G values were determined for all products identified after exposure to 10 000 rads. The major products were the sulfinic and sulfonic acids (CySO 2 H, CySO 3 H, and PenSO 2 H), the sulfhydryl derivatives (CySH and PenSH), symmetrical disulfides (CySSCy and PenSSPen), three trisulfides (CySSSCy, CySSSPen, and PenSSSPen), and ammonia. Each half of the disulfide behaved in exactly the same way as the corresponding symmetrical disulfide. Products from the CyS part of the disulfide were dose rate dependent while products from the PenS part were independent of dose rate. The reactions proposed for the symmetrical disulfides were adequate to explain radiolysis of the unsymmetrical disulfide.Radiolysis of a mixture of cystine and penicillamine disulfide was examined for comparison with the unsymmetrical disulfide and was found to give very similar results. It was concluded that the free radicals produced from the water attack each half at approximately equal rates.