Pyrroloquinoline quinone glucose dehydrogenase adopted in thermometric analysis for enhancement of glucose determination

Abstract

A broad measurement range of glucose is often required in clinical analysis, especially for diabetic patients where glucose levels can be very high. Pyrroloquinoline quinone glucose dehydrogenase (PQQGDH) has previously been used in electrochemical quantification of glucose with an extended linear range. However, in real sample determination of glucose, interferences from electroactive substances in blood are unavoidable. Calorimetric biosensors, e.g., the Enzyme Thermistor, are insensitive to either directly electroactive or optical interferences often present in real clinical samples. This paper describes a novel analytical strategy where the intrinsic advantages of PQQGDH are combined with the Enzyme Thermistor as biosensor using calorimetric detection as general measurement principle. When compared with the most frequently used enzyme glucose oxidase, PQQGDH has a higher catalytic efficiency and is insensitive to the availability of oxygen. The use of calorimetry in this context resulted in a broad linear range of glucose measurements, from 0.009 to 100 mM, an excellent specificity and insignificant side effects of compounds present in blood at high concentrations, such as lactate and urea.

Review—Glucose Monitoring Sensors: History, Principle, and Challenges

“…41 Enzyme thermistor is essentially a bioanalyzer based on a temperature sensor. 42 Glucose enzyme thermistor analyzes glucose level by probing for changes in heat generated in enzymatic reactions. It has a long-life performance more comparative analysis of clinical tests is needed for the measuring accuracy of blood glucose.…”

Direct Electrochemistry of Glucose Dehydrogenase-Functionalized Polymers on a Modified Glassy Carbon Electrode and Its Molecular Recognition of Glucose

“…NAD(P) + -dependent GDH can catalyze the production of β-D-glucose to D-glucose-δ-lactone and NAD(P) + as a cofactor to NAD(P)H [ 20 ]. NAD(P) + -dependent GDH has been shown to have higher activity compared to many other oxidoreductases that depend on other redox cofactors such as flavin adenine dinucleotide (FAD) [ 21 , 22 ], pyrroloquinoline quinone (PQQ) [ 23 , 24 ], and nicotinamide-dependent GDHs. NAD(P) + -dependent GDH does not permanently bind the cofactor within the enzyme but instead acts as a soluble co-substrate, with hydrogen acceptors and donors for intermediates in the reaction sequence.…”