title: Characterization of a novel lipolytic enzyme from Aspergillus oryzae.
abstract: In this study, we report the characterization of a protein from Aspergillus oryzae, exhibiting sequence identity with paraben esterase from the genus Aspergillus. The coding region of 1,586 bp, including a 77-bp intron, encoded a protein of 502 amino acids. The gene without the signal peptide of 19 amino acids was cloned into a vector, pPICZαC, and expressed successfully in Pichia pastoris as an active extracellular protein. The purified recombinant protein had pH and temperature optima of 7.0-8.0 and 30 °C, respectively, and was stable at the pH range of 7.0-10.0 and up to 40 °C. The optimal substrate for hydrolysis by the purified recombinant protein, among a panel of α-naphthyl esters (C2-C16), was α-naphthyl butyrate (C4), with activity of 0.16 units/mg protein. The considerable hydrolytic activity of the purified recombinant enzyme toward tributyrin was determined. However, no paraben esterase activity was detected toward the ethyl, propyl, and butyl esters of 4-hydroxybenzoic acid. In addition, no activity was detected toward the methyl esters of ferulic, p-coumaric, caffeic, and sinapic acids that would indicate feruloyl esterase activity.
authors.affiliation: Faculty of Agriculture, Yamagata University, 1-23 Wakaba-machi, Tsuruoka, Yamagata 997-8555, Japan. tkoseki@tds1.tr.yamagata-u.ac.jp
authors.forename: Takuya
authors.initials: T
authors.lastname: Koseki
authors.forename: Shungo
authors.initials: S
authors.lastname: Asai
authors.forename: Natsumi
authors.initials: N
authors.lastname: Saito
authors.forename: Masayo
authors.initials: M
authors.lastname: Mori
authors.forename: Yasuko
authors.initials: Y
authors.lastname: Sakaguchi
authors.forename: Kazutaka
authors.initials: K
authors.lastname: Ikeda
authors.forename: Yoshihito
authors.initials: Y
authors.lastname: Shiono
mesh_terms: D000595:Amino Acid Sequence; D001236:Aspergillus oryzae / Q000201:enzymology*; D003001:Cloning, Molecular; D004795:Enzyme Stability; D004950:Esterases / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D015870:Gene Expression; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D008969:Molecular Sequence Data; D010843:Pichia / Q000235:genetics; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D016415:Sequence Alignment; D013379:Substrate Specificity; D013696:Temperature; D014280:Triglycerides / Q000378:metabolism*
chemical_list: D011994:Recombinant Proteins; D014280:Triglycerides; D004950:Esterases; C005830:tributyrin