title: Purification and characterization of thermophilic xylanase isolated from the xerophytic-Cereus pterogonus sp.
abstract: A thermo stable xylanase was purified and characterized from the cladodes of Cereus pterogonus plant species. The enzyme was purified to homogeneity by ammonium sulfate (80%) fractionation, ion exchange and size exclusion chromatography. The enzyme showed a final specific activity of 216.2 U/mg and the molecular mass of the protein was 80 KDa. The optimum pH and temperature for xylanase activity were 5.0 and 80 °C, respectively. With oat spelt xylan as a substrate the enzyme yielded a Km value of 2.24 mg/mL and a Vmax of 5.8 μmol min(-1) mg(-1). In the presence of metal ions (1 mM) such as Co(2+),Mn(2+), Ni(2+), Ca(2+) and Fe(3+) the activity of the enzyme increased, where as strong inhibition of the enzyme activity was observed with the use of Hg(2+), Cd(2+), Cu(2+), while partial inhibition was noted with Zn(2+) and Mg(2+). The substrate specificity of the xylanase yielded maximum activity with oat spelt xylan.
authors.affiliation: Department of Biochemistry and Molecular Biology, School of Life Sciences, Pondicherry University, Kalapet, Puducherry, 605014, India.
authors.forename: Jeyaraman
authors.initials: J
authors.lastname: Vikramathithan
authors.forename: Gali Nirmal
authors.initials: GN
authors.lastname: Kumar
authors.forename: Pandurangan
authors.initials: P
authors.lastname: Muthuraman
authors.forename: Kotteazeth
authors.initials: K
authors.lastname: Srikumar
mesh_terms: D002845:Chromatography; D043364:Endo-1,4-beta Xylanases / Q000737:chemistry* / Q000302:isolation & purification*; D004795:Enzyme Stability; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D019684:Magnoliopsida / Q000737:chemistry / Q000201:enzymology*; D008970:Molecular Weight; D010940:Plant Proteins / Q000737:chemistry* / Q000302:isolation & purification*; D013379:Substrate Specificity; D014990:Xylans / Q000378:metabolism
chemical_list: D010940:Plant Proteins; D014990:Xylans; D043364:Endo-1,4-beta Xylanases
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