increased circulating enzyme level increased circulating gamma-glutamyl transferase level 2020-07-07T11:27:05Z MPheno.ontology increased circulating GGT level elevated blood level of the enzyme that catalyzes the transfer of gamma-glutamyl functional groups from molecules such as glutathione to an acceptor that may be an amino acid, a peptide or water (forming glutamate); GGT plays a key role in the gamma-glutamyl cycle, a pathway for the synthesis and degradation of glutathione as well as drug and xenobiotic detoxification; GGT is present in many organs throughout the body, with the highest concentrations found in liver, and elevated in the blood in most diseases that cause damage to the liver or bile ducts MP:0031114 increased circulating gamma-GT level increased circulating gamma-glutamyl transpeptidase level