L-cysteine metabolism in guinea pig and rat tissues

Rhodanese, gamma-cystathionase and 3-mercaptopyruvate sulfurtransferase activities were examined in guinea pig and rat liver, kidney and brain. In the liver of both species rhodanese showed the same high range of activity but in guinea pig kidney and brain a slightly lower level was determined than that in corresponding rat tissues. The 3-mercaptopyruvate sulfurtransferase and gamma-cystathionase activities in all the investigated tissues of guinea pig were significantly lower than those in rat. The sulfane sulfur pool, a source of sulfur transferred by rhodanese, can be augmented in vitro in guinea pig liver, but not in rat liver when 3-mercaptolactate-cysteine disulfide is used as a substrate of gamma-cystathionase.