Potential Application of N -Carbamoyl-β-Alanine Amidohydrolase from Agrobacterium tumefaciens C58 for β-Amino Acid Production

Abstract

ABSTRACT An N -carbamoyl-β-alanine amidohydrolase of industrial interest from Agrobacterium tumefaciens C58 (βcar At ) has been characterized. βcar At is most active at 30°C and pH 8.0 with N -carbamoyl-β-alanine as a substrate. The purified enzyme is completely inactivated by the metal-chelating agent 8-hydroxyquinoline-5-sulfonic acid (HQSA), and activity is restored by the addition of divalent metal ions, such as Mn 2+ , Ni 2+ , and Co 2+ . The native enzyme is a homodimer with a molecular mass of 90 kDa from pH 5.5 to 9.0. The enzyme has a broad substrate spectrum and hydrolyzes nonsubstituted N -carbamoyl-α-, -β-, -γ-, and -δ-amino acids, with the greatest catalytic efficiency for N -carbamoyl-β-alanine. βcar At also recognizes substrate analogues substituted with sulfonic and phosphonic acid groups to produce the β-amino acids taurine and ciliatine, respectively. βcar At is able to produce monosubstituted β 2 - and β 3 -amino acids, showing better catalytic efficiency ( k cat / K m ) for the production of the former. For both types of monosubstituted substrates, the enzyme hydrolyzes N -carbamoyl-β-amino acids with a short aliphatic side chain better than those with aromatic rings. These properties make βcar At an outstanding candidate for application in the biotechnology industry.