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

Abstract:Azoreductase from Pseudomonas putida WLY, which is a kind of induced and extracellular enzyme, was purified by Chromatographie 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°C. The specific activity of the purified enzyme was 8.22 x 10⁴U mg⁻¹. The K m value for X-3B was 39μM and the maximal velocity (V max ) was 12μmol 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.