Microbial production of next-generation stevia sweeteners.

Background: The glucosyltransferase UGT76G1 from Stevia rebaudiana is a chameleon enzyme in the targeted biosynthesis of the next-generation premium stevia sweeteners, rebaudioside D (Reb D) and rebaudioside M (Reb M). These steviol glucosides carry five and six glucose units, respectively, and have low sweetness thresholds, high maximum sweet intensities and exhibit a greatly reduced lingering bitter taste compared to stevioside and rebaudioside A, the most abundant steviol glucosides in the leaves of Stevia rebaudiana.

Results: In the metabolic glycosylation grid leading to production of Reb D and Reb M, UGT76G1 was found to catalyze eight different reactions all involving 1,3-glucosylation of steviol C - and C -bound glucoses.

Radioiodinated dechloro-4-iodofenofibrate: a hydrophobic model drug for molecular imaging studies.

Radiolabeling is a valuable option for tracking drug molecules in biodistribution experiments. In the development of innovative drug delivery systems the influence of the pharmaceutical formulation on the drugs' pharmacokinetics has to be investigated. The hypolipidemic agent fenofibrate is an ideal model drug for testing the performance of drug delivery systems designed for poorly soluble compounds.

De novo sequencing of peptides on single resin beads by MALDI-FTICR tandem mass spectrometry.

An efficient approach in combinatorial chemistry is the synthesis of one-bead-one-compound peptide libraries. In contrast to synthesis and functional screening, which is performed in a largely automated manner, structure determination has been frequently laborious and time-consuming. Here we report an approach for de novo sequencing of peptides on single beads by matrix-assisted laser desorption/ionization Fourier transform ion cyclotron resonance (MALDI-FTICR) tandem mass spectrometry, using a resin with a photolinker for solid-phase peptide synthesis.