The GT1 family of UDP-glycosyltransferases (UGTs) catalyze the transfer the glycosyl group from a nucleotide sugar, such as UDP-glucuronic acid, UDP-galactose, UDP-glucose or UDP-xylose, to a variety of small hydrophobic acceptor molecules (aglycones), resulting in more hydrophilic compounds that are efficiently excreted. Mammalian/vertebrate UGTs mainly use UDP-glucuronic acid as the sugar donor, whereas invertebrates and plants appear to use UDP-glucose as the main donor. Insect UGTs play a major role in the detoxification of substrates, cuticle formation, pigmentation and olfaction. The GT1 family is defined by a common protein structure and signature sequence of 44 amino acids responsible for binding the UDP moiety of the sugar donor. (Adapted from FBrf0152079 and PMID:26453144).