title: A new peroxidase from garlic (Allium sativum) bulb: its use in H2O2 biosensing.
abstract: Peroxidase POX(1) isoenzyme was purified from garlic (Allium sativum L.) bulb by ammonium sulfate precipitation, gel filtration and anion-exchange chromatography. Native-PAGE profile showed two isoforms, designated POX(1A) and POX(1B). POX(1B) seems to be more attractive for biosensor design since its K(m) (app) for H(2)O(2) is lower than that of POX(1A). In addition to its storage and operational stability, POX(1B) was found to be highly heat-stable, since almost 70% of its activity was conserved at 60 degrees C, whereas full activity was retained at 50 and 40 degrees C for 40 min. The optimal pH was approx. 5 and the optimal temperature was 30 degrees C. Next, gelatin was used as a matrix for enzyme immobilization on a gold electrode surface and electrochemical measurements were performed by using cyclic voltammetry. POX(1B)-based electrodes show great potential for application in H(2)O(2) monitoring of biological samples.
authors.affiliation: Bioengineering Unit 99 UR 09-26, INSAT (Institut National des Sciences Appliquées et de Technologie), Tunis, Tunisia.
authors.forename: Sarra
authors.initials: S
authors.lastname: El Ichi
authors.forename: Adnane
authors.initials: A
authors.lastname: Abdelghani
authors.forename: Imene
authors.initials: I
authors.lastname: Hadji
authors.forename: Salwa
authors.initials: S
authors.lastname: Helali
authors.forename: Ferid
authors.initials: F
authors.lastname: Limam
authors.forename: M Nejib
authors.initials: MN
authors.lastname: Marzouki
mesh_terms: D000645:Ammonium Sulfate / Q000737:chemistry; D015374:Biosensing Techniques / Q000379:methods*; D011232:Chemical Precipitation; D002850:Chromatography, Gel / Q000379:methods; D002852:Chromatography, Ion Exchange / Q000379:methods; D004563:Electrochemistry; D004566:Electrodes; D004795:Enzyme Stability; D004800:Enzymes, Immobilized; D005737:Garlic / Q000201:enzymology*; D005780:Gelatin / Q000494:pharmacology; D006046:Gold; D006861:Hydrogen Peroxide / Q000032:analysis*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D009195:Peroxidase / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism; D020033:Protein Isoforms / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism; D013696:Temperature
chemical_list: D004800:Enzymes, Immobilized; D020033:Protein Isoforms; D006046:Gold; D005780:Gelatin; D006861:Hydrogen Peroxide; D009195:Peroxidase; D000645:Ammonium Sulfate