Determination of haloalkane dehalogenase activity by capillary zone electrophoresis

A new sensitive method has been developed for the determination of haloalka ne dehalogenase activity. The enzymatic reactions were carried out directly in thermostatted autosampler vials and the formation of product - bromide or chloride ions - was monitored by sequential capillary zone electrophores is runs. The determinations were performed in a 75 mum fused-silica capilla ry using 5 mM chromate, 0.5 mM tetradecyltrimethylammonium bromide (pH 8.4) as a background electrolyte, separation voltage 15 kV (negative polarity) and indirect detection at sample wavelength 315 nm, reference wavelength 37 5 nm for brominated and chlorinated substrates, respectively 0.1 M beta -al anine-HCl (pH 3.50) as a background electrolyte, separation voltage 18 kV ( negative polarity) and direct detection at 200 nm for brominated substrates . The temperature of capillary was in both cases 25 degreesC. The method is rapid, can be automated, and requires only small amount of enzyme preparat ion and substrate. (C) 2000 Elsevier Science B.V. All rights reserved.