GSTT

GSTT, short for glutathione S-transferase theta, refers to the theta-class subgroup of the glutathione S-transferase (GST) superfamily. GSTs are detoxification enzymes that catalyze the conjugation of glutathione to a broad range of electrophilic compounds, aiding their solubility and elimination from the body. Theta-class GSTs are cytosolic enzymes that typically function as dimers and are expressed in several tissues, including the liver, lung, kidney, placenta, and others.

In humans, the best-characterized theta-class members are GSTT1 and GSTT2. These genes are located in a gene cluster on chromosome 22 and are subject to genetic polymorphisms that influence enzyme activity. A well-known feature of this class is the GSTT1 null allele, arising from a deletion that removes functional GSTT1; individuals can be GSTT1-present or GSTT1-null, with population frequencies varying by ethnicity. Copy-number variation for GSTT2 and related theta-class genes also occurs and can affect overall theta-class GST activity.

Clinical and scientific interest in GSTT focuses on their role in the metabolism of environmental toxins and potential impact on disease risk. Epidemiological studies have explored associations between GSTT1 and GSTT2 polymorphisms and susceptibility to cancers (such as lung and gastric cancer) and adverse responses to environmental exposures, including tobacco smoke and pollutants. Findings across studies are mixed and often depend on genetic background and exposure level. GSTT enzymes also participate in the metabolism of certain drugs and may influence oxidative stress and inflammatory responses. Research continues to clarify substrate scope, regulation, and clinical relevance of the GST theta class.