Glucuronidase Beta (GUSb)

Beta-glucuronidase is an enzyme that in humans is encoded by the GUSB gene.Human beta-glucuronidase is synthesized as an 80 kDa monomer (653 amino acids) before proteolysis removes 18 amino acids from the C-terminal end to form a 78 kDa monomer.  Biologically, beta-glucuronidase exists as a 332 kDa homotetramer.  Beta-glucuronidase contains several notable structural formations, including a type of beta barrel known as a jelly roll barrel and a TIM barrel.

Human beta-glucuronidase is homologous to the Escherichia coli enzyme beta-galactosidase.  This homologous relationship, along with the knowledge that glycosidases often perform hydrolysis catalyzed by two acidic residues, enabled the development of a mechanistic hypothesis.