title: Characterization of an α-amino-ɛ-caprolactam racemase with broad substrate specificity from Citreicella sp. SE45.
abstract: α-Amino-ε-caprolactam (ACL) racemizing activity was detected in a putative dialkylglycine decarboxylase (EC 4.1.1.64) from Citreicella sp. SE45. The encoding gene of the enzyme was cloned and transformed in Escherichia coli BL21 (DE3). The molecular mass of the enzyme was shown to be 47.4 kDa on SDS-polyacrylamide gel electrophoresis. The enzymatic properties including pH and thermal optimum and stabilities were determined. This enzyme acted on a broad range of amino acid amides, particularly unbranched amino acid amides including L-alanine amide and L-serine amide with a specific activity of 17.5 and 21.6 U/mg, respectively. The Kmand Vmaxvalues for D- and L-ACL were 5.3 and 2.17 mM, and 769 and 558 μmol/min.mg protein, respectively. Moreover, the turn over number (Kcat) and catalytic efficiency (Kcat/Km) of purified ACL racemase from Citreicella sp. SE45 using L-ACL as a substrate were 465 S-1and 214 S-1mM-1, respectively. The new ACL racemase from Citreicella sp. SE45 has a potential to be used as the biocatalytic application.
authors.affiliation: Department of Industrial Biotechnology, Faculty of Agro-Industry, Prince of Songkla University, Hat-Yai, 90112, Thailand.|Department of Biotechnology and Biotechnology Research Center, Toyama Prefectural University, 5180 Kurokawa, Imizu, Toyama, 939-0398, Japan.
authors.forename: Wisarut
authors.initials: W
authors.lastname: Payoungkiattikun
authors.affiliation: Department of Biotechnology and Biotechnology Research Center, Toyama Prefectural University, 5180 Kurokawa, Imizu, Toyama, 939-0398, Japan.|Asano Active Enzyme Molecule Project, ERATO, JST, 5180 Kurokawa, Imizu, Toyama, 939-0398, Japan.
authors.forename: Seiji
authors.initials: S
authors.lastname: Okazaki
authors.affiliation: Department of Biotechnology and Biotechnology Research Center, Toyama Prefectural University, 5180 Kurokawa, Imizu, Toyama, 939-0398, Japan.|Asano Active Enzyme Molecule Project, ERATO, JST, 5180 Kurokawa, Imizu, Toyama, 939-0398, Japan.
authors.forename: Atsutoshi
authors.initials: A
authors.lastname: Ina
authors.affiliation: Department of Industrial Biotechnology, Faculty of Agro-Industry, Prince of Songkla University, Hat-Yai, 90112, Thailand.
authors.forename: Aran
authors.initials: A
authors.lastname: H-Kittikun
authors.affiliation: Department of Biotechnology and Biotechnology Research Center, Toyama Prefectural University, 5180 Kurokawa, Imizu, Toyama, 939-0398, Japan. asano@pu-toyama.ac.jp.|Asano Active Enzyme Molecule Project, ERATO, JST, 5180 Kurokawa, Imizu, Toyama, 939-0398, Japan. asano@pu-toyama.ac.jp.
authors.forename: Yasuhisa
authors.identifier: 0000-0003-3645-3952
authors.initials: Y
authors.lastname: Asano
mesh_terms: D000577:Amides / Q000378:metabolism; D000596:Amino Acids / Q000378:metabolism; D002209:Caprolactam / Q000378:metabolism*; D004492:Edetic Acid / Q000494:pharmacology; D004795:Enzyme Stability; D004926:Escherichia coli / Q000235:genetics; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008670:Metals / Q000494:pharmacology; D008970:Molecular Weight; D019998:Racemases and Epimerases / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D041902:Rhodobacteraceae / Q000201:enzymology* / Q000235:genetics; D013379:Substrate Specificity; D013696:Temperature
chemical_list: D000577:Amides; D000596:Amino Acids; D008670:Metals; D002209:Caprolactam; D004492:Edetic Acid; D019998:Racemases and Epimerases
keywords: ACL racemase; Citreicella sp. SE45; D-amino acids; Enzyme characterization; PLP-dependent enzyme