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Applied and Environmental Microbiology, January 2009, p. 514-520, Vol. 75, No. 2
0099-2240/09/$08.00+0 doi:10.1128/AEM.01128-08
Copyright © 2009, American Society for Microbiology. All Rights Reserved.

Departamento de Química-Física, Bioquímica y Química Inorgánica, Edificio CITE I, Universidad de Almería, La Cañada de San Urbano, E-04120 Almería, Spain,1 Dipartimento di Chimica, Materiali, Ingegneria Chimica G. Natta, Politecnico di Milano, Milan, Italy2
Received 19 May 2008/ Accepted 10 November 2008
An N-carbamoyl-β-alanine amidohydrolase of industrial interest from Agrobacterium tumefaciens C58 (βcarAt) has been characterized. βcarAt 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 Mn2+, Ni2+, and Co2+. 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-
-, -β-, -
-, and -
-amino acids, with the greatest catalytic efficiency for N-carbamoyl-β-alanine. βcarAt also recognizes substrate analogues substituted with sulfonic and phosphonic acid groups to produce the β-amino acids taurine and ciliatine, respectively. βcarAt is able to produce monosubstituted β2- and β3-amino acids, showing better catalytic efficiency (kcat/Km) 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 βcarAt an outstanding candidate for application in the biotechnology industry.
Published ahead of print on 14 November 2008.
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