Science of The Total Environment 1992-08-12

Degradation of aliphatic halogen-substituted pesticides by dehalogenase isolated from Pseudomonas alcaligenes. Identification and properties of the enzyme.

M D Busto, P P Smith, M Pérez-Mateos, R G Burns

Index: Sci. Total Environ. 123-124 , 267-77, (1992)

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Abstract

Some characteristics of a 2,2-dichloropropionate dehalogenase induced in a bacterial strain capable of degrading high concentrations of the herbicide dalapon were studied. Polyacrilamide gel electrophoresis of the crude cell free extracts identified only one type of dehalogenase. The single enzymatic protein showed activity against a variety of chlorinated aliphatic acids but differed in their activity levels. Thus activity in mumol substrate converted (mg protein)-1 min-1 was 2-monochloropropionate 0.65, 2,2-dichloropropionate 0.56, 2-monochloroacetate 1.70 and 2,2-dichloroacetate 1.00. In the crude extracts, the enzyme activity against 2,2-dichloropropionate was optimal at a broad pH range with a mid-point at pH 9.5 and apparent Km values were within the range 0.23-0.73 mM.