Glucuronic Glucuronidase

Enzymes hydrolyzing UDP-glucuronic acid (UDP-glucuronic acid pyrophosphatase) and j8-D-glucuronosides ()8-glucuronidase) are present in microsomal material. Their activities in tissues depend on the species examined (G4, P2, W15). 

Glucose, mandelamine, and hydrochlorothorazide decrease the amount of estriol found when acid hydrolysis is used to release estriol from its conjugate with glucuronic acid in urine. The destruction of estriol in diabetic urine can be monitored by the inclusion of internal standards of labeled estriol glucuronide and reduced by prior dilution of the urine. When glucuronidase is used to release the estriol, the results are not affected when glucose of diabetic urine is present. When this is done the internal standard is not necessary. 

It has been known since 1905 that ether glucuronides, as glycosides, may be hydrolyzed by a variety of enzyme preparations, e. g., emulsin hydrolyzes euxanthic acid,10 phenyl D-glucuronide10 and camphor-D-glucuronic acid.69-60 The enzyme responsible, /3-glucuronidase, appears... 

Levvy193 were unable to observe conjugation of o-aminophenol with D-glu-curonic acid in the presence of a /3-D-glucuronidase preparation. No conjugation was found in a similar system, using /3-D-glucuronic acid 1-phosphate.22 194... 

It would seem that, at present, the data demand the interpretation that /3-D-glucuronidase is a purely hydrolytic enzyme that it does not catalyze glucosiduronic acid synthesis that it may, in some cases, be associated with rapid, cell division, and that its apparent relationship to estrogen and to cancer is probably on this basis and, finally, that, although its adaptive characteristics have not been disproved, they are unlikely to exist. If they should exist, the basis is most probably the hydrolytic function. It would seem that /3-D-glucuronidase bears the same relationship to glucuronic conjugates that phenolsulfatase bears to ester sulfates. 

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