Small molecule drugs undergo phase II glucuronidation and sulfation in the liver to facilitate excretion into various biological fluids. β-glucuronidase and sulfatase are used to hydrolyze the metabolites, enabling more sensitive and accurate quantitation of the metabolites by mass spectrometry (MS). Any contamination in these enzymes affects not only the effectiveness of the enzyme but may also alter the analytes, skewing the outcome. We demonstrated esterase contamination in various commercial β-glucuronidase enzymes by utilizing a fluorescent substrate. Contaminated enzymes showed the conversion of 6-monoacetylmorphine (6-MAM), a specific metabolite of heroin, to morphine, which can skew the readout to false negative for heroin usage.
This poster was presented at MSACL 2017 in Palm Springs. Download a copy here.