title: Characterization of Sphingomonas sp. JB13 exo-inulinase: a novel detergent-, salt-, and protease-tolerant exo-inulinase.
abstract: A glycoside hydrolase family 32 exo-inulinase gene was cloned from Sphingomonas sp. JB13 and expressed in Escherichia coli BL21 (DE3). The purified recombinant enzyme (rInuAJB13) showed an apparently optimal activity at pH 5.5 and 55 °C and remained activity at 10-70 °C. The addition of most metal ions and chemical reagents showed little or no effect (retaining more than 76.5 % activity) on the enzyme activity, notably the addition of surfactants SDS, CTAB, Tween 80, and Triton X-100. Most local liquid detergents, including Balin, Walch, Ariel, Tide, Tupperware, and Bluemoon, also showed little or no effect (retaining more than 77.8 % activity) on the enzyme activity. rInuAJB13 exhibited 135.3-163.6 % activity at the NaCl concentration of 1.0-4.5 M. After incubation with up to 57.0 mg mL(-1) trypsin and 90.0 mg mL(-1) proteinase K at 37 °C for 60 min (pH 7.2), rInuAJB13 retained more than 80 % of its initial activity. The enzyme presents a high proportion (28.0 %) of amino acid residues G, A, and V. This paper is the first to report a detergent-, salt-, and protease-tolerant exo-inulinase.
authors.affiliation: Engineering Research Center of Sustainable Development and Utilization of Biomass Energy, Ministry of Education, Yunnan Normal University, Kunming, 650500, People's Republic of China.
authors.forename: Junpei
authors.initials: J
authors.lastname: Zhou
authors.forename: Mozhen
authors.initials: M
authors.lastname: Peng
authors.forename: Rui
authors.initials: R
authors.lastname: Zhang
authors.forename: Junjun
authors.initials: J
authors.lastname: Li
authors.forename: Xianghua
authors.initials: X
authors.lastname: Tang
authors.forename: Bo
authors.initials: B
authors.lastname: Xu
authors.forename: Junmei
authors.initials: J
authors.lastname: Ding
authors.forename: Yajie
authors.initials: Y
authors.lastname: Gao
authors.forename: Junrong
authors.initials: J
authors.lastname: Ren
authors.forename: Zunxi
authors.initials: Z
authors.lastname: Huang
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D001483:Base Sequence; D003902:Detergents / Q000737:chemistry; D004795:Enzyme Stability; D006026:Glycoside Hydrolases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D009994:Osmolar Concentration; D059748:Proteolysis; D055049:Salt Tolerance; D020578:Sphingomonas / Q000201:enzymology* / Q000235:genetics
chemical_list: D001426:Bacterial Proteins; D003902:Detergents; D006026:Glycoside Hydrolases; C023086:inulinase