The glutathione peroxidase-like catalysis of α-(phenylselenenyl) ketones was investigated. Degradation studies demonstrated the rapid cleavage of the aliphatic carbon-selenium bond of α-(phenylselenenyl) ketones by glutathione at pH 6.9 in a methanolic phosphate buffer under argon. On treatment with excess glutathione under aerobic conditions, α- (phenylselenenyl) ketones, S-(phenylselenenyl) glutathione and diphenyl diselenide were ...