Investigation of Immobilized Enzymes for Hydrolysis of Glucuronides in Urine.

摘要

Metabolism of certain drugs leads to the formation of conjugation products with glucuronic acid prior to excretion in urine. Thus, heroin is converted to morphine, which after conjugation with glucuronic acid, appears in the urine as morphine glucuronide. Detection systems for drug glucuronide products can be improved if the glucuronide is hydrolyzed as a first step in the system. The report contains the results of an investigation of immobilized beta-glucuronidase to hydrolyze urinary glucuronides such as morphine-3-glucuronide. beta-glucuronidases from three sources were immobilized on porous glass beads and CNBr-activated sepharose. The activity of the soluble and immobilized enzymes was determined in batch assays using phenolphthalein glucuronide and p-nitrophenyl glucuronide. The enzymatic activity, stability, and effect of pH on beta-glucuronidase columns were determined at 37C using p-nitrophenyl glucuronide and morphine glucuronide as substrates. The efficacy of hydrolyzing morphine glucuronide in urine by columns of immobilized beta-glucuronidase was also investigated.