University Of Tehran Press Pollution 2383-451X 3 4 2017 10 01 Biochemical characterization of recombinant benzyl alcohol dehydrogenase from Rhodococcus ruber UKMP-5M 613 622 62777 10.22059/poll.2017.62777 EN Arezoo Tavakoli Department of Nursing, Faculty of Nursing, Islamic Azad University, Eghlid Branch, Eghlid, Iran Ainon Hamzah School of Biosciences and Biotechnology, Faculty of Science and Technology, National University of Malaysia, Selangor, Malaysia Journal Article 2017 04 02 Benzyl Alcohol Dehydrogenase (BADH) is an important enzyme for hydrocarbon degradation, which can oxidize benzyl alcohols to aldehydes, while being capable of catalyzing a reversible reaction by reducing benzaldehyde. BADH is a member of medium chain alcohol dehydrogenases, in which zinc and NAD are essential for enzyme activity. This paper describes the expression, purification, and characterization of recombinant benzyl alcohol dehydrogenase, encoded by xylB gene from Rhodococcus ruber UKMP-5M. The gene has been amplified and cloned into E. coli, and the recombinant plasmid pGEMT-xylB has been digested by NdeI and HindIII to construct plasmid pET28b-xylC and then ligated into E. coli BL21 (DE3), itself induced by 0.3 mM isopropyl β-D-thiogalactoside (IPTG) at 25°C. The expressed BADH has been 38 kDa, and is purified by affinity chromatography, in which the specific activity was 30 U/mg after 17 folds purification, leading to a NAD-dependent enzyme that uses benzyl alcohol as a substrate for enzyme characterization. The final metabolite is benzaldehyde, identified by gas chromatography mass spectrometry (GC-MS). The BADH activity has been 0.7 U/mL and the optimum pH and temperature, 9.5 and 30ºC, respectively. Also the Michaelis constant (Km) and maximum velocity (Vmax) have accounted to 705 µM and 1.3 U/mL, respectively. Benzyl alcohol dehydrogenase from R. ruber UKMP-5M can be used for hydrocarbon biodegradation in contaminated sites.

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