Sulfotransferases are transferase enzymes that catalyze the transfer of a sulfo group (not a sulfate group) from a donor molecule to an acceptor alcohol or amine. The most common sulfo group donor is  3'-phosphoadenosine-5'-phosphosulfate (PAPS). In the case of alcohol as acceptor, the product is a sulfate (R-OSO₃^-), whereas an amine leads to a sulfo-amine (R-NH-SO₃^-). Both reactive groups for a sulfonation via sulfotransferases may be part of a protein, lipid, carbohydrate or steroid.