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 (PubMed:18719240, PubMed:23288867). Essential for the elimination and detoxification of drugs, xenobiotics and endogenous compounds (PubMed:18719240, PubMed:23288867). Catalyzes the glucuronidation of the endogenous estrogen hormones such as estradiol and estriol (PubMed:18719240, PubMed:23288867). glucuronate acceptor + UDP-alpha-D-glucuronate = acceptor beta-D-glucuronoside + H(+) + UDP 17alpha-estradiol + UDP-alpha-D-glucuronate = 17alpha-estradiol 17-O-(beta-D-glucuronate) + H(+) + UDP 16alpha,17alpha-estriol + UDP-alpha-D-glucuronate = 16alpha,17alpha-estriol 17-O-(beta-D-glucuronate) + H(+) + UDP Some kinetic parameters were assessed using commercial enzymes, which may represent a mix of both active and inactive protein forms, and therefore modify the kinetic values. Belongs to the UDP-glycosyltransferase family. UGT2B4 has been previously described as an enzyme named UGT2B11. However the name UGT2B11 has now been reused for another human protein (see AC O75310).