Abstract
Cysteine and methionine were oxidized to sulphate by slices of rat liver suspended in bicarbonate Ringer solution. Sulphate estimations were carried out by a modification of the colorimetric method which employs benzidine as the precipitant. Glutathione was oxidized only after hydrolysis and cystine only after reduction. S-ethyl cysteine was slowly oxidized and ergothioneine not at all.