GGT1 Gene: Gamma-Glutamyltransferase 1 – Function, Disease, and Expression | Biomedical Database

The GGT1 gene encodes gamma-glutamyltransferase 1, a membrane-bound enzyme that catalyzes the transfer of gamma-glutamyl groups from glutathione and other gamma-glutamyl compounds to acceptors such as amino acids and peptides. This enzyme plays a critical role in glutathione metabolism, maintaining cellular redox balance, and detoxifying xenobiotics. GGT1 is expressed on the surface of cells in various tissues, particularly in the kidney, liver, and biliary epithelium. Elevated serum GGT activity is a common clinical marker for hepatobiliary disease and alcohol abuse. Additionally, GGT1 has been implicated in cancer progression, where it contributes to tumor growth and resistance to oxidative stress.

Tissue Expression

Cell Line Expression

Hotspot Mutations

Mutation functional classification

• Glutathione metabolism (Reactome: R-HSA-174403)

• Metabolism of amino acids and derivatives (Reactome: R-HSA-71291)

• Detoxification of Reactive Oxygen Species (Reactome: R-HSA-3299685)

Gamma-glutamyltransferase 1 is a heterodimeric enzyme composed of a heavy and a light chain, derived from a single precursor protein. It is anchored to the plasma membrane via its N-terminal hydrophobic domain. The enzyme catalyzes the cleavage of gamma-glutamyl bonds in glutathione, transferring the gamma-glutamyl moiety to water (hydrolysis) or to amino acids/peptides (transpeptidation). This reaction is essential for the degradation of glutathione and the recycling of cysteine, a rate-limiting step in glutathione homeostasis. GGT1 is highly expressed in tissues with secretory or absorptive functions, such as the renal proximal tubules, bile ducts, and pancreatic acinar cells. Its activity is modulated by oxidative stress and inflammatory cytokines. In cancer, GGT1 overexpression is linked to increased resistance to chemotherapy and radiation, making it a potential therapeutic target.