Biochemical characterization of a novel thermostable chitinase from Hydrogenophilus hirschii strain KB-DZ44.

Autor: Bouacem K; Laboratory of Cellular and Molecular Biology (LCMB), Microbiology Team, Faculty of Biological Sciences, University of Sciences and Technology of Houari Boumediene (USTHB), PO Box 32, El Alia, Bab Ezzouar, 16111 Algiers, Algeria; Laboratory of Microbial Biotechnology and Engineering Enzymes (LMBEE), Centre of Biotechnology of Sfax (CBS), University of Sfax, Road of Sidi Mansour Km 6, PO Box 1177, Sfax 3018, Tunisia., Laribi-Habchi H; Laboratory of Functional Analysis of Chemical Processes (LFACP), Process Engineering Department, Faculty of Technology, University of Blida 1, Road of Soumaâ, PO Box 270, 09000 Blida, Algeria. Electronic address: larhassiba@yahoo.fr., Mechri S; Laboratory of Microbial Biotechnology and Engineering Enzymes (LMBEE), Centre of Biotechnology of Sfax (CBS), University of Sfax, Road of Sidi Mansour Km 6, PO Box 1177, Sfax 3018, Tunisia., Hacene H; Laboratory of Cellular and Molecular Biology (LCMB), Microbiology Team, Faculty of Biological Sciences, University of Sciences and Technology of Houari Boumediene (USTHB), PO Box 32, El Alia, Bab Ezzouar, 16111 Algiers, Algeria., Jaouadi B; Laboratory of Microbial Biotechnology and Engineering Enzymes (LMBEE), Centre of Biotechnology of Sfax (CBS), University of Sfax, Road of Sidi Mansour Km 6, PO Box 1177, Sfax 3018, Tunisia. Electronic address: bassem.jaouadi@yahoo.fr., Bouanane-Darenfed A; Laboratory of Cellular and Molecular Biology (LCMB), Microbiology Team, Faculty of Biological Sciences, University of Sciences and Technology of Houari Boumediene (USTHB), PO Box 32, El Alia, Bab Ezzouar, 16111 Algiers, Algeria. Electronic address: amelbouanane@gmail.com.
Jazyk: angličtina
Zdroj: International journal of biological macromolecules [Int J Biol Macromol] 2018 Jan; Vol. 106, pp. 338-350. Date of Electronic Publication: 2017 Aug 05.
DOI: 10.1016/j.ijbiomac.2017.08.026
Abstrakt: An extracellular acido-thermostable endo-chitinase (called ChiA-Hh59) from thermophilic Hydrogenophilus hirschii strain KB-DZ44, was purified and characterized. The maximum chitinase activity recorded after 36-h of incubation at 60°C was 3000U/ml. Pure enzyme was obtained after heat and acidic treatment, precipitation by ammonium sulphate and acetone, respectively, followed by sequential column chromatographies on Sephacryl S-200 and Mono Q-Sepharose. Based on Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF/MS) analysis, the purified enzyme is a monomer with a molecular mass of 59103.12-Da. The 22 residue NH 2 -terminal sequence of the enzyme showed high homology with family-18 bacterial chitinases. The optimum pH and temperature values for chitinase activity were pH 5.0 and 85°C, respectively. The pure enzyme was completely inhibited by p-chloromercuribenzoic acid (p-CMB) and N-ethylmaleimide (NEM). The obtained results suggest that ChiA-Hh59 might be an endo-chitinase. The studied chitinase exhibited high activity towards colloidal chitin, chitin azure, glycol chitin, while it did not hydrolyse chitibiose and amylose. Its K m and k cat values were 0.298mg colloidal chitin/ml and 14400s -1 , respectively. Its catalytic efficiency was higher than those of chitodextrinase and ChiA-65. Additionally, Thin-layer chromatography (TLC) analysis from chitin-oligosaccharides showed that ChiA-Hh59 acted as an endo-splitting enzyme. In conclusion, this chitinase may have great potential for the enzymatic degradation of chitin.
(Copyright © 2017 Elsevier B.V. All rights reserved.)
Databáze: MEDLINE
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