Theγ-Glutamyl Cycle

The γ-glutamyl cycle consists of six enzyme-catalyzed reactions that account for the synthesis and degradation of glutathione, a tripeptide that is found in virtually all living cells. It has been proposed that the γ-glutamyl cycle functions in the transport of amino acids across cell membranes. The status of research on the γ-glutamyl cycle is considered. There is evidence that the cycle functions in the kidney and in other tissues. Patients with diseases associated with a deficiency of a specific enzyme of the γ-glutamyl cycle have been found, and the nature of the biochemical defects has been explored.