Purification and Characterization of Beta-Glucuronidase From Escherichia Coli HGU-3, a Human Intestinal Bacterium

Biol Pharm Bull. 1995 Sep;18(9):1184-8. doi: 10.1248/bpb.18.1184.


beta-Glucuronidase was purified 360-fold from Escherichia coli HGU-3, an human intestinal bacterium. The specific activity of the purified enzyme was 17.78 units/mg protein. The enzyme (M.W. 290000) is composed of four subunits (M.W. 72000) with a pI and optimal pH of 4.8 and 6-7, respectively. The apparent Km for p-nitrophenyl-beta-D-glucuronide was found to be 0.22 mM. The enzyme was inhibited by saccharic acid 1,4-lactone, glycyrrhizin, N-ethylmaleimide (NEM) and p-chloromercuriphenylsulfonic acid (PCMS). Using the bile containing bilirubin diglucuronide as a substrate, the purified beta-glucuronidase was able to hydrolyze it to bilirubin. This hydrolyzed bilirubin formed calcium bilirubinate with a reaction mixture containing CaCl2.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bilirubin / metabolism
  • Escherichia coli / enzymology*
  • Glucuronidase / isolation & purification*
  • Humans
  • Hydrogen-Ion Concentration
  • Intestines / microbiology*
  • Molecular Weight


  • Glucuronidase
  • Bilirubin