UDP-glucuronosyltransferase (UGT) that catalyzes phase II biotransformation reactions in which lipophilic substrates are conjugated with glucuronic acid to increase the metabolite's water solubility, thereby facilitating excretion into either the urine or bile. Essential for the elimination and detoxification of drugs, xenobiotics and endogenous compounds. Involved in the glucuronidation of the AGTR1 angiotensin receptor antagonist zolarsatan, a drug which can inhibit the effect of angiotensin II. glucuronate acceptor + UDP-alpha-D-glucuronate = acceptor beta-D-glucuronoside + H(+) + UDP UDP-alpha-D-glucuronate + zolasartan = UDP + zolarsartan-1-N-beta-D-glucuronide Homodimer. Homooligomer. Interacts with UGT1A1, UGT1A3, UGT1A4, UGT1A6, UGT1A7, UGT1A8, UGT1A9 and UGT1A10 to form heterodimers. UGT1A5 is one of the isoforms produced at the UGT1A complex locus. The UGT1A complex locus produces different isoforms based on alternative use of promoters, first exons and terminal exons. Belongs to the UDP-glycosyltransferase family.