Estrogen sulfotransferase (EST)

Estrogen sulfotransferase (abbreviated as EST, gene symbol SULT1E1) is a cytosolic phase II conjugating enzyme that catalyzes the transfer of a sulfate group from 3′-phosphoadenosine-5′-phosphosulfate (PAPS) to the hydroxyl group of estrogens (notably estrone and estradiol), converting them into their sulfated, inactive forms such as estrone sulfate. This modification increases water solubility and prevents estrogens from binding to estrogen receptors, thereby down-regulating their hormonal activity. SULT1E1 is mainly involved in the regulation of estrogen homeostasis but also acts on other substrates including dehydroepiandrosterone (DHEA) and several xenobiotics. Its expression is detected in multiple tissues including liver, breast, adipose tissue, endometrium, and brain, and is implicated in the pathophysiology of hormone-dependent cancers due to its regulatory control over estrogen availability. Certain drugs—including synthetic estrogens and tamoxifen metabolites—are also substrates for SULT1E1, and gene polymorphisms or altered expression levels have been associated with disease risk and variable drug responses.

Other names

Estrone sulfotransferaseSULT1E1ESTSulfotransferase 1E1Estrogen sulfotransferase 1

Sulfation (inactivation via sulfonation of estrogens and certain drugs, thereby regulating their bioavailability and interaction with estrogen receptors)