Characterization of 1-chlorohexane halidohydrolase, a dehalogenase of wide substrate range from an Arthrobacter sp.
نویسندگان
چکیده
1-Chlorohexane halidohydrolase from Arthrobacter sp. strain HA1 was purified to homogeneity by fractional precipitation, ion-exchange chromatography, gel filtration, and high-performance liquid chromatography gel filtration. The enzyme was a monomer with a molecular weight of about 37,000; its amino acid composition and N-terminal sequence were determined. The enzyme had a broad optimum around pH 9.5, a temperature optimum near 50 degrees C, an activation energy of 40 kJ/mol, and a molecular activity of 0.9 kat/mol. The substrate range of the enzyme included at least 50 halogenated compounds. 1-Chloroalkanes (C3 to C10), 1-bromoalkanes (C1 to C9), and 1-iodoalkanes (C1 to C7), but no 1-fluoroalkane, were substrates. Subterminally substituted, branched-chain, and nonsaturated haloalkanes were dehalogenated. Some halogenated aromatic substrates, e.g., bromobenzene and benzyl bromide, were hydrolyzed. Several alpha,omega-dihaloalkanes were subject to double dehalogenation. Thus, 1,2-dibromoethane was hydrolyzed first to 2-bromoethanol and then to 1,2-dihydroxyethane. Crude extracts of strain HA1 were found to contain a debrominase that cleaved bromoalkanes with long alkyl chains.
منابع مشابه
Three dehalogenases and physiological restraints in the biodegradation of haloalkanes by Arthrobacter sp. strain HA1.
Arthrobacter sp. strain HA1 utilizes 18 C2-to-C8 1-haloalkanes for growth and synthesizes an inducible 1-bromoalkane debrominase of unknown physiological function (R. Scholtz, T. Leisinger, F. Suter, and A.M. Cook, J. Bacteriol. 169:5016-5021, 1987) in addition to an inducible 1-chlorohexane halidohydrolase which dehalogenates some 50 substrates, including alpha, omega-dihaloalkanes. alpha, ome...
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ورودعنوان ژورنال:
- Journal of bacteriology
دوره 169 11 شماره
صفحات -
تاریخ انتشار 1987