Gamma-Glutamyltransferase 1 (gGT1)

Gamma-Glutamyltransferase 1 (gGT1) belongs to the gamma-glutamyltransferase family. It is a heterodimer, consists of two polypeptide chains, a heavy chain and a light chain. The active site of gGT1 is located in the light chain. gGT1 is activated by autocatalytic cleavage, and cleaved by autocatalysis into a large and a small subunit, the autocatalytic cleavage is essential to the functional activation of gGT1. gGT1 is crucial for metabolism of glutathione, it can cleave the gamma-glutamyl bond of extracellular glutathione (gamma-Glu-Cys-Gly), glutathione conjugates (such as MCTR1) and other gamma-glutamyl compounds (such as leukotriene C4). gGT1 is used as a diagnostic marker for liver diseases. Besides, in diseases of the liver, pancreas and biliary system, gGT1 activity in serum is elevated. Slightly elevated levels of serum gGT1 has also been found to be associated with cardiovascular diseases. And gGT1 is expressed at high levels in many different tumors.