Jim Blasberg , Harkewal Singh , Kevin Ray
Sigma-Aldrich, St. Louis, MO
β-glucuronidase (GUS) enzymes are utilized to hydrolyze glucuronide (gluc) drug metabolites to the parent drug, facilitating analysis by LC-MS/MS. Here we evaluate the hydrolysis efficiency of β-glucuronidase derived from Patella vulgata (limpet), Helix pomatia (snail), Red abalone, and E. coli on drugs of abuse and pain management in a synthetic urine matrix. Hydrolysis efficiencies vary from product to product and several parameters need to be investigated in determining which enzyme to use.
Dimer of β-GUS (inset: expanded view of active site)
One Fishman1 unit will liberate 1 μg phenolphthalein from phenolphthalein glucuronide per hour at 37οC All hydrolysis experiments were normalized for enzyme activity, i.e. equivalent Fishman units