Cytosolic sulfotransferases catalyze the sulfonation of many hormones, neurotransmitters, drugs, and xenobiotic compounds. They are distinct from Golgi-resident sulfotransferases by the absence of transmembrane domains and are located in the cytoplasm. SULT1C2 is mainly expressed in the gastrointestinal tract stomach, duodenum, jejunum, ileum, colon, caecum and rectum), liver and kidneys, but not in the lungs. In contrast, SULT1C4, a sulfotransferase that is most closely related to SULT1C2, is expressed at higher levels in fetal lung and kidney and at lower levels in fetal heart. So far, SULT1C2 is found to be active only on pnitrophenol. The enzymatic activity of our recombinant human SULT1C2 was determined using a phosphatase coupled assay.