Abstract
Abstract Arginine deiminase is an enzyme used to biosynthesize L-citrulline from L-arginine. The arginine deiminase gene of Enterococcus faecalis SK32.001 was expressed in Escherichia coli with a specific activity of 131.2 U mg−1. The expressed enzyme was a dimer with a subunit molecular weight of 49.1 kDa. It was stable in a pH range of 5.0–5.5 and in a temperature range of 20 °C to 25 °C. The optimum pH and temperature of the enzyme were 5.5 and 55 °C, respectively. Fe3+ enhanced its enzymatic activity. The chemical modifiers and the three-dimensional structural model of the recombinant enzyme indicated that Lys, Trp and Cys were very important amino acid residues to the enzyme. It’s Km and Vmax for L-arginine were 10.1 mM and 378.1 μmol min−1 mg−1, respectively. The bioproductions of L-citrulline with the resting recombinant cells at 30 °C and 45 °C were 97.4 g L−1 and 96.9 g L−1, respectively.
Published Version
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