Glutathione Transferases as Efficient Ketosteroid Isomerases.

ABSTRACT: In addition to their well-established role in detoxication, glutathione transferases (GSTs) have other biological functions. We are focusing on the ketosteroid isomerase activity, which appears to contribute to steroid hormone biosynthesis in mammalian tissues. A highly efficient GST A3-3 is present in some, but not all, mammals. The alpha class enzyme GST A3-3 in humans and the horse shows the highest catalytic efficiency with k_cat/K_m values of approximately 10⁷ M^-1s^-1, ranking close to the most active enzymes known. The expression of GST A3-3 in steroidogenic tissues suggests that the enzyme has evolved to support the activity of 3β-hydroxysteroid dehydrogenase, which catalyzes the formation of 5-androsten-3,17-dione and 5-pregnen-3,

SUBMITTER: Mannervik B 

PROVIDER: S-EPMC8645602 | biostudies-literature | 2021

REPOSITORIES: biostudies-literature