Conjugation of acetaldehyde with cysteinylglycine, the first metabolite in glutathione breakdown by gamma-glutamyltranspeptidase.

Glutathione and its metabolites were examined for reactivity to acetaldehyde. When acetaldehyde was incubated with glutathione alone, there was only a slight decrease of acetaldehyde, while an apparently equimolar reaction between acetaldehyde and free sulfhydryl was observed with the addition of gamma-glutamyltranspeptidase. Cysteinylglycine, the first metabolite in the glutathione breakdown by gamma-glutamyltranspeptidase, showed a rapid and equimolar reactivity to acetaldehyde and such was comparable to the reaction seen with L-cysteine or D-penicillamine. In light of the chemical structure, cysteinylglycine probably conjugates with acetaldehyde to form thiazolidinecarboxylic acid derivatives, 2-methyl-thiazolidine-4-carbonyl-glycine, and if so, the alteration of glutathione metabolism by acetaldehyde during ethanol intoxication warrants further attention.