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. Catalyzes the glucuronidation of endogenous estrogen hormone estradiol. Contributes to bile acid (BA) detoxification by catalyzing the glucuronidation of BA substrates, which are natural detergents for dietary lipids absorption. Potential role in detoxification of toxic waste compounds in the amniotic fluid before birth, and air-born chemical after birth. glucuronate acceptor + UDP-alpha-D-glucuronate = acceptor beta-D-glucuronoside + H(+) + UDP 17alpha-estradiol + UDP-alpha-D-glucuronate = 17alpha-estradiol 3-O-(beta-D-glucuronate) + H(+) + UDP 17beta-estradiol + UDP-alpha-D-glucuronate = 17beta-estradiol 3-O-(beta-D-glucuronate) + H(+) + UDP chenodeoxycholate + UDP-alpha-D-glucuronate = chenodeoxycholoyl-24-O-(beta-D-glucuronate) + UDP lithocholate + UDP-alpha-D-glucuronate = lithocholoyl-24-O-(beta-D-glucuronate) + UDP deoxycholate + UDP-alpha-D-glucuronate = deoxycholoyl-24-O-(beta-D-glucuronate) + UDP hyocholate + UDP-alpha-D-glucuronate = hyocholoyl-24-O-(beta-D-glucuronate) + UDP hyodeoxycholate + UDP-alpha-D-glucuronate = H(+) + hyodeoxycholate 6-O-(beta-D-glucuronate) + UDP UGT2A2 isoform is part of the UGT2A complex locus which displays alternative use of promoters and exons. The locus is defined by 2 alternative promoters resulting in 2 fonctionally active polypeptides UGT2A1 and UGT2A2. Alternative splicing of exons results in additional isoforms for each protein class. Belongs to the UDP-glycosyltransferase family.