Glucuronidation is the most common phase II modification and plays an important role in human clearance metabolism. Glucuronidated metabolites have also been linked to disease development and microbiota–host co‐metabolism. Although many of these compounds have been identified, the total number of unknown glucuronides and their impact on the human host's physiology can only be estimated. Herein, we describe the combination of an untargeted metabolomics analysis and enzymatic metabolic conversion for the selective detection of glucuronide conjugates by using UPLC‐MS/MS in human urine samples. Our study demonstrates that this powerful strategy can be used for the selective identification of glucuronidated molecules and to discover unknown natural metabolites. In total, we identified 191 metabolites in a single sample including microbiota‐derived compounds as well as previously unidentified molecules.

A rapid and efficient method the exploiting affinity of a-amylase for its substrate starch is described. a-amylase from Bacillus licheniformis was purified to homogeneity by ammonium sulphate precipitation and affinity chromatography with 230-fold purification. The a-amylase adsorption to various starches was examined in order to screen its ability for highest binding to starch. The a-amylase was bound to starch more tenaciously, hence various eluants like maltose, soluble starch and high salts could not elute the bound a-amylase. However, the bound a-amylase was instantly eluted using 2% (w/v) dextrin. The purified enzyme showed a single polypeptide on SDS-PAGE, with a molecular weight of 58 kD. Western blot analysis confirmed the specificity of antibody raised against purified a-amylase.

No abstract