title: Enhancement of stability of immobilized glucose oxidase by modification of free thiols generated by reducing disulfide bonds and using additives.
abstract: Stability of glucose oxidase (GOD) immobilized with lysozyme has been considerably enhanced by modification of free thiols generated by reducing disulfide bonds using beta-mercaptoethanol and N-ethylmaleimide in conjunction with additives like antibiotics and salts. Thermal stability of immobilized GOD was quantified by means of the transition temperature, Tm and the operational stability by half-life t1/2 at 70 degrees C. Modification of the free thiols in the enzyme coupled with the presence of kanamycin, NaCl, and K2SO4, led to increase in Tm, to 80, 82 and 84 degrees C (compared to 75 degrees C in control) and t1/2 by 7.7-, 11- and 22-fold, respectively, indicating that this method can be effectively used for enhancing the stability of enzymes.
authors.affiliation: Department of Fermentation Technology and Bioengineering, Central Food Technological Research Institute, Mysore 570013, India.
authors.forename: K C
authors.initials: KC
authors.lastname: Gulla
authors.forename: M D
authors.initials: MD
authors.lastname: Gouda
authors.forename: M S
authors.initials: MS
authors.lastname: Thakur
authors.forename: N G
authors.initials: NG
authors.lastname: Karanth
mesh_terms: D015374:Biosensing Techniques / Q000295:instrumentation* / Q000379:methods; D020099:Coated Materials, Biocompatible / Q000138:chemical synthesis / Q000737:chemistry; D004220:Disulfides / Q000737:chemistry*; D004566:Electrodes; D004795:Enzyme Stability; D004800:Enzymes, Immobilized / Q000737:chemistry; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005609:Free Radicals / Q000737:chemistry; D005949:Glucose Oxidase / Q000737:chemistry*; D010084:Oxidation-Reduction; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013438:Sulfhydryl Compounds / Q000737:chemistry*; D013696:Temperature
chemical_list: D020099:Coated Materials, Biocompatible; D004220:Disulfides; D004800:Enzymes, Immobilized; D005609:Free Radicals; D013438:Sulfhydryl Compounds; D005949:Glucose Oxidase