title: Purification and thermal characterization of a novel peroxidase from a local chick pea cultivar.
abstract: A novel peroxidase isolated from a local chick pea (Cicer arietinum L.) cultivar (Balksar 2000) was purified by means of ammonium sulfate precipitation, DEAE-cellulose chromatography and two runs on gel filtration. The purified enzyme has a specific activity of 2045 U/mg with 17 % activity recovery. The molecular mass of the enzyme was estimated to be 39 kDa by SDS-polyacrylamide gel electrophoresis. Optimum pH and temperature of the enzyme were 5.5 and 45 degrees C respectively. The thermal denaturation of local chick pea peroxidase was studied in aqueous solution at temperatures ranging from 45 degrees C to 65 degrees C. The temperature of 50% inactivation of the enzyme was found to be 68 degrees C. The enthalpy (DeltaH*) and free energy (DeltaG*) of thermal denaturation of chick pea peroxidase were 101.4 and 103.4 k J/mol respectively at 65 degrees C. Metals like Zn2+, Mn2+, Hg2+, Co2+ and Al3+ slightly inhibited the peroxidase activity while Ca2+, Mg2+ and Ba2+ have no effect on enzyme activity. The high specific activity and thermal stability make chick pea peroxidase an alternative to horseradish peroxidase (HRP) in various applications.
authors.affiliation: Industrial Biotechnology Laboratory, Department of Chemistry, University of Agriculture, Faisalabad, Pakistan-38040. hnbhatti2005@yahoo.com
authors.forename: H N
authors.initials: HN
authors.lastname: Bhatti
authors.forename: A
authors.initials: A
authors.lastname: Najma
authors.forename: M
authors.initials: M
authors.lastname: Asgher
authors.forename: M A
authors.initials: MA
authors.lastname: Hanif
authors.forename: M A
authors.initials: MA
authors.lastname: Zia
mesh_terms: D000645:Ammonium Sulfate / Q000737:chemistry; D002848:Chromatography, DEAE-Cellulose / Q000379:methods; D029863:Cicer / Q000201:enzymology*; D004789:Enzyme Activation / Q000187:drug effects; D004795:Enzyme Stability / Q000187:drug effects; D006863:Hydrogen-Ion Concentration; D008670:Metals / Q000494:pharmacology; D009195:Peroxidase / Q000737:chemistry* / Q000302:isolation & purification* / Q000378:metabolism; D013696:Temperature; D013816:Thermodynamics
chemical_list: D008670:Metals; D009195:Peroxidase; D000645:Ammonium Sulfate