Characterization of two 3-deoxy-d-Arabino-Heptulosonate 7-phosphate synthases from Bacillusmethanolicus.

3-Deoxy-d-arabino-heptulosonate 7-phosphate (DAHP) synthase catalyzes the condensation of phosphoenolpyruvate (PEP) with d-erythrose 4-phosphate (E4P) and plays an important role in regulating carbon flux toward aromatic amino acid biosynthesis in bacteria and plants. Sequence analysis of the DAHP synthases AroG1 and AroG2 from Bacillus methanolicus MGA3 suggested this thermophilic, methylotrophic bacterium possesses two type Iβ DAHP synthases. This study describes production of AroG1 and AroG2 in Escherichia coli as hexa-histidine fused proteins, which were purified by affinity chromatography.

A Fluorescence-Based Assay System for the Determination of Haloperoxidase-Activity Using a Two-Dimensional Calibration Ap-proach.

Screening for an interesting biocatalyst and its subsequent kinetic characterization depends on a reliable activity assay. In this work, a fluorometric assay based on the halogenation of 4-methyl-7-diethylamino-coumarin was established to monitor haloperoxidase-activity. Since haloperoxidases utilize hydrogen peroxide and halide ions to halogenate a broad range of substrates by releasing hypohalous acids, a direct quantification of haloperoxidase-activity remains difficult.