using spectrophotometric determination of 1-chloro-2,4-dinitrobenzene (CDNB) conjugation with reduced glutathione (1 mM) in 100 mM NaPO4 (pH 6.5) at room temperature.

Glutathione S-transferase alpha 4 (GSTA4) is an enzyme that in humans is encoded by the GSTA4 gene. Glutathione S-transferases (GSTs) are a family of enzymes that play an important role in detoxification by catalyzing the conjugation of many hydrophobic and electrophilic compounds with reduced glutathione. Based on their biochemical, immunologic, and structural properties, cytosolic and membrane-bound forms of glutathione S-transferase are encoded by two distinct supergene families. At present, eight distinct classes of the soluble cytoplasmic mammalian glutathione S-transferases have been identified: alpha, kappa, mu, omega, pi, sigma, theta and zeta. The GSTs are thought to function in xenobiotic metabolism and play a role in susceptibility to cancer, and other diseases.

This gene encodes a glutathione S-tranferase belonging to the alpha class. The alpha class genes, which are located in a cluster on chromosome 6, are highly related and encode enzymes with glutathione peroxidase activity that function in the detoxification of lipid peroxidation products. Reactive electrophiles produced by oxidative metabolism have been linked to a number of degenerative diseases including Parkinson′s disease, Alzheimer′s disease, cataract formation, and atherosclerosis.

The enzyme should be used by the end-user customer within 1 year of receipt.