Kim D H, Jin Y H, Jung E A, Han M J, Kobashi K
College of Pharmacy, Kyung-Hee University, Seoul, Korea.
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.
β-葡萄糖醛酸酶从人肠道细菌大肠杆菌HGU-3中纯化出来，纯化倍数为360倍。纯化后酶的比活性为17.78单位/毫克蛋白。该酶（分子量290000）由四个亚基（分子量72000）组成，其等电点和最适pH分别为4.8和6 - 7。对硝基苯基-β-D-葡萄糖醛酸的表观米氏常数为0.22 mM。该酶受到糖二酸1,4-内酯、甘草甜素、N-乙基马来酰亚胺（NEM）和对氯汞苯磺酸（PCMS）的抑制。以含有胆红素二葡萄糖醛酸酯的胆汁为底物，纯化后的β-葡萄糖醛酸酶能够将其水解为胆红素。这种水解后的胆红素与含有氯化钙的反应混合物形成胆红素钙。
