Unique characteristics of rat spleen lymphocyte, L1210 lymphoma and HeLa cells in glutathione biosynthesis from sulfur-containing amino acids

Suspensions of rat spleen lymphocyte, murine L1210 lymphoma and HeLa cells were partially depleted of glutathione (GSH) with diethyl maleate and allowed to utilize either 35S]methionine, 35S]cystine or 35S]-cysteine for GSH synthesis. Lymphocytes preferentially utilized cysteine, compared to cystine, at a ratio of about 30 to 1, which was not related to differences in the extent of amino acid uptake. Only HeLa cells displayed a slight utilization of methionine via the cystathionine pathway for cysteine and GSH biosynthesis. HeLa and L1210 cells readily utilized either cystine or cysteine for GSH synthesis. The three cell types accumulated detectable levels of intracellular cysteine glutathione mixed disulfide when incubated in a medium containing a high concentration of cystine. Various enzyme activities were measured including gamma-glutamyl transpeptidase, GSH S-transferase and gamma-cystathionase. These results support the concept of a dynamic interorgan relationship of GSH to plasma cyst(e)ine that may have importance for growth of various cell types in vivo.