title: A low perfusion rate microreactor for continuous monitoring of enzyme characteristics: application to glucose oxidase.
abstract: This report describes a versatile and robust microreactor for bioactive proteins physically immobilized on a polyether sulfone filter. The potential of the reactor is illustrated with glucose oxidase immobilized on a filter with a cut-off value of 30 kDa. A flow-injection system was used to deliver the reactants and the device was linked on-line to an electrochemical detector. The microreactor was used for on-line preparation of apoglucose oxidase in strong acid and its subsequent reactivation with flavin adenine dinucleotide. In addition we describe a miniaturized version of the microreactor used to assess several characteristics of femtomole to attomole amounts of glucose oxidase. A low negative potential over the electrodes was used when ferrocene was the mediator in combination with horseradish peroxidase, ensuring the absence of oxidation of electro-active compounds in biological fluids. A low backpressure at very low flow rates is an advantage, which increases the sensitivity. A variety of further applications of the microreactor are suggested.
authors.affiliation: University of Groningen, University Medical Centre Groningen (UMCG), Department Psychiatry, Hanzeplein 1, 9713 EZ, Groningen, The Netherlands. truus.posthuma@wur.nl
authors.forename: G A
authors.initials: GA
authors.lastname: Posthuma-Trumpie
authors.forename: K
authors.initials: K
authors.lastname: Venema
authors.forename: W J H
authors.initials: WJ
authors.lastname: van Berkel
authors.forename: J
authors.initials: J
authors.lastname: Korf
mesh_terms: D015374:Biosensing Techniques / Q000379:methods*; D004563:Electrochemistry; D004566:Electrodes; D004800:Enzymes, Immobilized; D005296:Ferrous Compounds / Q000737:chemistry; D005182:Flavin-Adenine Dinucleotide / Q000737:chemistry; D017022:Flow Injection Analysis; D005949:Glucose Oxidase / Q000032:analysis* / Q000378:metabolism; D006735:Horseradish Peroxidase / Q000737:chemistry; D007700:Kinetics; D008567:Membranes, Artificial; D000075163:Metallocenes; D008851:Micropore Filters; D008970:Molecular Weight; D010084:Oxidation-Reduction; D011108:Polymers / Q000737:chemistry*; D012680:Sensitivity and Specificity; D013450:Sulfones / Q000737:chemistry*
chemical_list: D004800:Enzymes, Immobilized; D005296:Ferrous Compounds; D008567:Membranes, Artificial; D000075163:Metallocenes; D011108:Polymers; D013450:Sulfones; D005182:Flavin-Adenine Dinucleotide; C022840:polyether sulfone; D005949:Glucose Oxidase; D006735:Horseradish Peroxidase; C004998:ferrocene