GSTA3
GSTA3 (glutathione S-transferase alpha 3) is a cytosolic member of the alpha class of glutathione S-transferases. It conjugates reduced glutathione to hydrophobic electrophiles and catalyses double-bond isomerisation steps in the biosynthesis of steroid hormones. Browse Assay Genie's current range of GSTA3 research reagents below, or read on for the biology behind the target.
GSTA3 catalyses the conjugation of reduced glutathione to a wide range of exogenous and endogenous hydrophobic electrophiles, a reaction that underlies cellular defence against toxic, carcinogenic and pharmacologically active electrophilic compounds. It shows substantial activity toward aflatoxin B1-8,9-epoxide. Beyond detoxification, GSTA3 has a distinct role in endocrine biochemistry: it efficiently catalyses the obligatory double-bond isomerisation of delta(5)-androstene-3,17-dione and delta(5)-pregnene-3,20-dione, the precursors of testosterone and progesterone respectively, and so contributes to steroid hormone biosynthesis.
The GSTA3 gene encodes a protein of the GST superfamily, alpha family, and belongs to the HGNC group of soluble glutathione S-transferases. Cytosolic and membrane-bound glutathione S-transferases are encoded by two distinct supergene families, and eight classes of soluble cytoplasmic mammalian enzymes have been described: alpha, kappa, mu, omega, pi, sigma, theta and zeta. The alpha class genes lie in a cluster on chromosome 6. UniProt records the GSTA3 protein in the cytoplasm. An additional transcript variant has been reported, although its full-length sequence has not been determined.
Alpha class genes are highly related, and their enzymes typically show glutathione peroxidase activity. GSTA3 diverged during evolution, accumulating mutations in the active site that changed its substrate specificity and catalytic activity relative to its relatives. This divergence is consistent with its efficient steroid isomerase function. Orthologous genes named Gsta3 are present in mouse and rat, which allows comparative work on glutathione S-transferase function in common model species.
GSTA3 isomerises precursors of testosterone and progesterone, making it a relevant enzyme for studying steroidogenic pathways.
The enzyme conjugates glutathione to electrophiles and acts on aflatoxin B1-8,9-epoxide, supporting research on cellular defence against toxic compounds.
Glutathione S-transferases protect cells from carcinogenic electrophiles, so GSTA3 is of interest in studies of chemical carcinogenesis.
Active-site mutations distinguish GSTA3 from related alpha class enzymes, offering a model for how substrate specificity and catalytic activity diverge.
GSTA3 conjugates reduced glutathione to hydrophobic electrophiles, contributing to cellular defence against toxic and carcinogenic compounds. It also catalyses double-bond isomerisation of delta(5)-androstene-3,17-dione and delta(5)-pregnene-3,20-dione, precursors of testosterone and progesterone, and has substantial activity toward aflatoxin B1-8,9-epoxide.
The HGNC name is glutathione S-transferase alpha 3, and UniProt lists the protein as glutathione S-transferase A3. No other aliases are recorded. NCBI Gene notes an additional transcript variant, but its full-length sequence has not been determined, so isoform details remain unresolved.
Yes. Mouse and rat both have an ortholog named Gsta3, so the gene can be studied in common model species. GSTA3 belongs to the alpha family of the GST superfamily; check the datasheet of any product for its validated reactivity.
Other alpha class glutathione S-transferases from the same gene cluster on chromosome 6, with products at Assay Genie.
Gene and protein annotations from HGNC, NCBI Gene and UniProt Q16772; product specifications from Assay Genie datasheets.