A Novel Recombinant β-Glucuronidase Enzyme for Improved Drug Analysis

β-glucuronidase plays an important role in the analysis of biological fluids for the presence of drug metabolites. This enzyme hydrolyzes glucuronide metabolites back to the native parent drug. The use of β-glucuronidase is often necessary when extensive drug metabolism complicates drug detection. The b-Glucuronidase derived from limpets (Patella vulgata) has been used for many years as the enzyme of choice for the hydrolysis of drug-glucuronides in urine tests. Although the native enzyme from limpets is robust and has broad specificity its use is limited due to its low purity, and the limited availability of high quality raw material for production.

For the development of a next-generation recombinant enzyme, we have cloned the β-glucuronidase gene from Patella vulgata, expressed it in a proprietary expression system to obtain a highly pure and defined enzyme. The recombinant enzyme is highly purified to minimize protein content that can interfere with the analytical methods used. It is devoid of monoacetylmorphine (MAM) esterase activity (6-monoacetylmorphine → morphine) that interferes with discrimination between morphine and heroin, and is highly active against the traditionally difficult opioid substrate, Codeine-6-β-D-glucuronide. In addition, the enzyme is highly stable and active in a wide temperature range.