ENZYME CATALYSIS AND DECOLOURISATION OF BRILLIANT REACTIVE RED X-3B BY AZOREDUCTASE FROM A NEWLY ISOLATED PSEUDOMONAS PUTIDA WLY

Azoreductase from Pseudomonas putida WLY, which is a kind of induced and extracellular enzyme, was purified by chromatographic methods. The purified azoreductase, with a molecular weight of 28,000Da, gave a single band on SDS-PAGE. The maximal azoreductase activity was observed at pH 7.0 and 35 degrees C. The specific activity of the purified enzyme was 8.22 x 10(4)U mg(-1). The K-m value for X-3B was 39 mu M and the maximal velocity (V-max) was 12 mu mol of X-3B min(-1) mg(-1). The purified azoreductase catalyses the reductive cleavage of the azo bond of X-3B in the presence of NADH as electron donor and yields aniline. The purified azoreductase is inhibited by several metal ions, including Fe2+ and Ca2+, and is activated by Mg2+. The result of eliminating the plasmid of P. putida WLY showed that the azoreductase coding gene locates in the plasmid DNA.