title: Purification and characterisation of an acidic and antifungal chitinase produced by a Streptomyces sp.
abstract: An extremely acidic extracellular chitinase produced by a Streptomyces sp. was purified 12.44-fold by ammonium sulphate precipitation, ion-exchange chromatography and gel-permeation chromatography and further characterised. The molecular mass of the enzyme was estimated to be about 40 kDa by SDS-PAGE. The optimum pH and temperature of the purified enzyme were pH 2 and 6, and 50 °C respectively. The enzyme showed high stability in the acidic pH range of 2-6 and temperature stability of up to 50 °C. Additionally, the effect of some cations and other chemical compounds on the chitinase activity was studied. The activity of the enzyme was considerably retained under salinity conditions of up to 3%. The Km and Vmax values of the enzyme were determined to be 6.74 mg mL(-1) and 61.3 U mg(-1) respectively using colloidal chitin. This enzyme exhibited antifungal activity against phytopathogens revealing a potential biocontrol application in agriculture.
authors.affiliation: CSIR-National Institute for Interdisciplinary Science and Technology, Thiruvananthapuram 695019, Kerala, India.
authors.forename: Narayanan
authors.initials: N
authors.lastname: Karthik
authors.affiliation: CSIR-National Institute for Interdisciplinary Science and Technology, Thiruvananthapuram 695019, Kerala, India. Electronic address: binodkannur@niist.res.in.
authors.forename: Parameswaran
authors.initials: P
authors.lastname: Binod
authors.affiliation: CSIR-National Institute for Interdisciplinary Science and Technology, Thiruvananthapuram 695019, Kerala, India.
authors.forename: Ashok
authors.initials: A
authors.lastname: Pandey
mesh_terms: D000935:Antifungal Agents / Q000737:chemistry*; D002412:Cations; D002686:Chitin / Q000737:chemistry; D002688:Chitinases / Q000096:biosynthesis*; D002852:Chromatography, Ion Exchange; D003102:Colloids / Q000737:chemistry; D004591:Electrophoresis, Polyacrylamide Gel; D006863:Hydrogen-Ion Concentration; D007218:Industrial Microbiology / Q000379:methods*; D007477:Ions; D007526:Isoelectric Point; D007700:Kinetics; D008670:Metals / Q000737:chemistry; D008970:Molecular Weight; D012997:Solvents / Q000737:chemistry; D013302:Streptomyces / Q000201:enzymology*; D013379:Substrate Specificity; D013696:Temperature
chemical_list: D000935:Antifungal Agents; D002412:Cations; D003102:Colloids; D007477:Ions; D008670:Metals; D012997:Solvents; D002686:Chitin; D002688:Chitinases
keywords: Antifungal activity; Characterisation; Chitinase; Purification; Streptomyces sp.