γ-Glutamyltranspeptidases: sequence, structure, biochemical properties, and biotechnological applications

gamma-Glutamyltranspeptidases (gamma-GTs) are ubiquitous enzymes that catalyze the hydrolysis of gamma-glutamyl bonds in glutathione and glutamine and the transfer of the released gamma-glutamyl group to amino acids or short peptides. These enzymes are involved in glutathione metabolism and play critical roles in antioxidant defense, detoxification, and inflammation processes. Moreover, gamma-GTs have been recently found to be involved in many physiological disorders, such as Parkinson's disease and diabetes. In this review, the main biochemical and structural properties of gamma-GTs isolated from different sources, as well as their conformational stability and mechanism of catalysis, are described and examined with the aim of contributing to the discussion on their structure-function relationships. Possible applications of gamma-glutamyltranspeptidases in different fields of biotechnology and medicine are also discussed.