Ly. Xun, PURIFICATION AND CHARACTERIZATION OF CHLOROPHENOL 4-MONOOXYGENASE FROM BURKHOLDERIA-CEPACIA AC1100, Journal of bacteriology, 178(9), 1996, pp. 2645-2649
Burkholderia (formerly Pseudomonas) cepacia AC1100 mineralizes the her
bicide 2,4,5-trichlorophenoxyacetate (2,4,5-T), and the first intermed
iate of 2,4,5-T degradation is 2,4,5-trichlorophenol. Chlorophenol 4-m
onooxygenase activity responsible for 2,4,5-trichlorophenol degradatio
n was detected in the cell extract. The enzyme consisted of two compon
ents separated during purification, and both were purified to more tha
n 95% homogeneity, The reconstituted enzyme catalyzed the hydroxylatio
n of several tested chlorophenols,vith the coconsumption of NADH and o
xygen. In addition to chlorophenols, the enzyme also hydroxylated some
chloro-p-hydroquinones with the coconsumption of NADH and oxygen. App
arently, the single enzyme was responsible for converting 2,4,5-trichl
orophenol to 2,5-dichloro-p-hydroquinone and then to 5-chlorohydroxyqu
inol (5-chloro-1,2,4-trihydroxybenzene). Component A had a molecular w
eight of 22,000 and contained flavin adenine dinucleotide. Component A
alone catalyzed NADH-dependent cytochrome c reduction, indicating tha
t it had reductase activity. Component B had a molecular weight of 58,
000, and no catalytic activity has yet been shown by itself.