Estrone sulfotransferase (EST) (EC 2.8.2.4), also known as estrogen sulfotransferase, is an enzyme that catalyzes the transformation of an unconjugated estrogen like estrone into a sulfated estrogen like estrone sulfate. It is a steroid sulfotransferase and belongs to the family of transferases, to be specific, the sulfotransferases, which transfer sulfur-containing groups. This enzyme participates in androgen and estrogen metabolism and sulfur metabolism. Estrone sulfotransferase (EST) (EC 2.8.2.4), also known as estrogen sulfotransferase, is an enzyme that catalyzes the transformation of an unconjugated estrogen like estrone into a sulfated estrogen like estrone sulfate. It is a steroid sulfotransferase and belongs to the family of transferases, to be specific, the sulfotransferases, which transfer sulfur-containing groups. This enzyme participates in androgen and estrogen metabolism and sulfur metabolism. Steroid sulfatase is an enzyme that catalyzes the reverse reaction, the transfer of a sulfate to an unconjugated estrogen. In enzymology, an EST is an enzyme that catalyzes the following chemical reaction: Thus, the two substrates of this enzyme are 3'-phosphoadenylyl sulfate and estrone, whereas its two products are adenosine 3',5'-bisphosphate and estrone 3-sulfate. The enzyme also catalyzes the same reaction for estradiol, with estradiol sulfate as the product. Two enzymes have been identified that together are thought to represent estrone sulfotransferase (EST): As of late 2007, 5 structures have been solved for this class of enzymes, with PDB accession codes 1AQU, 1AQY, 1BO6, 1G3M, and 1HY3. The systematic name of this enzyme class is 3'-phosphoadenylyl-sulfate:estrone 3-sulfotransferase. Other names in common use include 3'-phosphoadenylyl sulfate-estrone 3-sulfotransferase, estrogen sulfotransferase, estrogen sulphotransferase, oestrogen sulphotransferase, and 3'-phosphoadenylylsulfate:oestrone sulfotransferase.