GLUCURONIDATION OF LIPOPHILIC SUBSTRATES - PREPARATION OF 3-BENZO[A]PYRENYL-BETA-D-GLUCOPYRANOSIDURONIC ACID IN MULTIMILLIGRAM QUANTITIES BY MICROSOMAL UDP-GLUCURONYL TRANSFERASE

A convenient method for the enzymic conversion of multimilli-gram quantities of 3-hydroxybenzo[a]pyrene to 3-benzo[a]pyrenyl-β-D-glucopyranosiduronic acid in 90% yield is described. Commercially available freeze-dried rabbit liver microsomes were incubated in the presence of UDPGA, 3-hydroxybenzo[a]pyrene and Triton X-100 detergent (Figure 1). The course of the biosynthetic reaction was followed by fluorimetry. The glucuronide product was extracted from the acidified incubation supernate with ethyl acetate and the acid function of the glucuronide was utilized in an acid-base extraction procedure to purify the glucuronide from biological and unreacted starting material. The glucuronide precipitated from ethyl acetate and was collected by centrifugation. High pressure liquid chromatography and spectroscopic techniques were used to verify the structure and purity of 3-benzo[a]-pyrenyl-β-D-glucopyranosiduronic acid. © 1979, Taylor & Francis Group, LLC. All rights reserved.