UDP-glucuronosyltransferases catalyze phase II biotransformation reactions in which lipophilic substrates are conjugated with glucuronic acid to increase water solubility and enhance excretion. They are of major importance in the conjugation and subsequent elimination of potentially toxic xenobiotics and endogenous compounds (By similarity). glucuronate acceptor + UDP-alpha-D-glucuronate = acceptor beta-D-glucuronoside + H(+) + UDP Belongs to the UDP-glycosyltransferase family.