Purification and properties of a plasmid-encoded 2,4-dichlorophenol hydroxylase

2,4-Dichlorophenol hydroxylase, an enzyme involved in the bacterial degradation of the herbicide 2,4-dichlorophenoxyacetate (2,4-D) was purified from two bacterial strains that harbored the same 2,4-D plasmid, pJP4. The purified enzymes (Mr 224 000) from the two transconjugants were indistinguishable; they contained FAD and were composed of non-identical subunits, Mr 67 000 and 45 000, respectively. Various substituted phenols were hydroxylated, using either NADH or NADPH. The amino acid composition of the native enzyme was determined.