Human Glucuronosyltransferase 1A1/UGT1A1 Alexa Fluor™ Plus 680-conjugated Antibody

UGT1A1 (UDP-glucuronosyltransferase 1-A1; also UDPGT 1-1 and HUG-BR1) is a 52-57 kDa member of the UGT1A subfamily, UGT family of enzymes. UGT1A1 is expressed by the liver, and catalyzes the conjugation of glucuronic acid (GA) from UDPGA to lipophilic acceptors such as (anti-cancer) drugs and bilirubin. Addition of glucuronic acid increases target solubility and facilitates elimination. Mature human UGT1A1 is a 508 amino acid (aa) type I transmembrane ER glycoprotein. It contains a 465 aa luminal domain (aa 26-490) plus a 26 aa cytoplasmic region. The luminal domain is unusual in that aa 157-176 are embedded in the ER membrane. Amino acids 29-444 contain the enzyme active site. The cytoplasmic tail appears to mediate noncovalent homodimerization, and heterodimerization with UGT2B. The signal sequence (aa 1-25) is normally cleaved, but a Lys15Arg mutation blocks insertion into the ER membrane. There are multiple point mutations that impact enzyme activity. One potential splice form is reported that shows a six aa substitution for aa 289-533. Over aa 60-186, human UGT1A1 shares 64% aa identity with mouse UGT1A1.