[Isoform 1]: Involved in biotransformation reactions in which lipophilic substrates are conjugated with sugars to increase water solubility and enhance excretion. Such reactions are of major importance in the elimination of potentially toxic xenobiotics and endogenous compounds. UGT3A2 catalyzes the addition of sugar residues from UDP-glucose and UDP-xylose to a broad range of acceptor substrates including 4-methylumbelliferone, 1-hydroxypyrene, bioflavones, and estrogens (PubMed:21088224). It has negligible activity toward bile acids and androgens (PubMed:21088224). To a lesser extent, is also able to use UDP-galactose but is inactive with UDP-glucuronic acid or UDP-N- acetylglucosamine as sugar donors (PubMed:21088224, PubMed:22621930). . [Isoform 2]: Lacks UDP-glycosyltransferase activity. . This is the function of ENSG00000168671 (UGT3A2, UDP glycosyltransferase family 3 member A2).