Isolation and characterization of l-tryptophan ammonia lyase from rubrivivax benzoatilyticus strain ja2

Abstract

Ammonia lyase belongs to the family of enzymes that catalyzes the deamination of amino acids. Depending on the relative activity towards the substrates, L-tryptophan ammonia lyase converts L-tryptophan to indole 3-acrylic acid and ammonia. Here, we isolated, purified, and characterized an L-tryptophan ammonia lyase from phototrophic purple non-sulfur bacterium Rubrivivax benzoatilyticus JA2. The isolated L-tryptophan ammonia lyase found to catalyze the reaction of L-tryptophan to produce indole 3-acrylic acid and NH3. The enzyme is a heterotetramer and has the highest affinity to L-tryptophan. The optimum pH and temperature for the enzymatic action were 7.5 and 35oC, respectively and the Km and Vmax were 40.4 + 23.1 nM and 0.964+0.2046 s-1, respectively. These results suggest that the isolated enzyme is highly bioactive and could be a new class. Further molecular analyses are required to confirm the novelty of the enzyme.