Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.2.1.31 (beta-glucuronidase)
 7,680 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

This procedure was developed as an overall benzodiazepine confirmation scheme and includes the detection of the most important urinary analytes encountered by clinical toxicology laboratories in North America: alpha-hydroxyalprazolam, alpha-hydroxytriazolam, 2-hydroxyethylflurazepam, oxazepam, temazepam, and lorazepam. Desmethyldiazepam (nordiazepam) was not targeted because it is metabolized to oxazepam. This procedure takes advantage of beta-glucuronidase hydrolysis for analysis of intact benzodiazepine molecules, oxazepam-2H5 as an internal standard, a newly developed extraction solvent, and a silylating moiety that may be more sensitive than trimethylsilyl (-TMS) derivatives, the tertbutyldimethylsilyl (-TBDMS) derivative. For all compounds the extraction efficiency was greater than 90% and the limit of quantitation (LOQ at a S/N of 10) was less than 10 ng/mL. Coefficients of variation for a 200-ng/mL control were less than 5% and less than or equal to 11% for within-run and between-run trials, respectively. Of 13 human specimens screened by EMIT and most with self-reported histories, alpha-hydroxyalprazolam was found in seven (range 49-1264 ng/mL), oxazepam was found in five (72-3897 ng/mL), and lorazepam (476 ng/mL), 2-hydroxyethylflurazepam (2301 ng/mL), and alpha-hydroxytriazolam (106 ng/mL) in one each.
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PMID:Urinalysis of alpha-hydroxyalprazolam, alpha-hydroxytriazolam, and other benzodiazepine compounds by GC/EIMS. 150 66

beta-Glucuronidase is an enzyme often employed to de-conjugate beta-glucuronides during urinary drug testing for benzodiazepines. It is commonly accepted that use of beta-glucuronidase is a preferred method of hydrolysis over acid-catalyzed hydrolysis, which is known to induce benzodiazepine degradation and transformation. Literature to date, however, has not reported any cases of benzodiazepine transformation initiated by commercial beta-glucuronidase products. In this study, urine specimens containing either oxazepam or oxazepam glucuronide were incubated with beta-glucuronidase enzymes obtained from Escherichia coli, Helix pomatia, and Patella vulgata under various incubation conditions. After liquid-liquid extraction, the extract was analyzed by both liquid chromatography-tandem mass spectrometry and gas chromatography-mass spectrometry for the presence of benzodiazepines. All three enzyme preparations examined were capable of reducing oxazepam or oxazepam glucuronide into nordiazepam (desmethyldiazepam). Nordiazepam formation was positively correlated with incubation temperature, incubation time, oxazepam concentration, and enzyme concentration. Under all enzymatic hydrolysis conditions investigated, the percentage of nordiazepam formation is < 2.5% relative to the amount of oxazepam present in the system. The findings of this study have both clinical and forensic implications, and it is clear that the detection of nordiazepam in biological samples subjected to testing involving enzyme-catalyzed hydrolysis should be interpreted with care.
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PMID:A novel reductive transformation of oxazepam to nordiazepam observed during enzymatic hydrolysis. 2052 58