Hexokinase immobilization

A schematic of fee QCM instrument is shown in Figure 1. Two QCM crystals are used in the experiments, so that detection is done in a differential mode. One is termed fee active crystal, which has hexokinase immobilized by entitqipment in a poly(acrylamide) gel. The other is termed the reference crystal, which has bovine serum albumin (BS A) immobilized in exactly fee same way. A similar differential mode technique, utilizing piezoelectric cystals, has been previously decribed using a... 

Fig. 4. Schematic of a multisequence biosensor in which the target glucose is first converted to glucose-6-phosphate, G6P, in the test solution by hexokinase. G6P then reacts selectively with glucose-6-phosphate dehydrogenase immobilized on the quartz crystal surface. Electrons released in the reaction then chemically reduce the Pmssian blue film (see Fig. 3), forcing an uptake of potassium ions. The resulting mass increase is manifested as a...

For instance, for the immobilization of710 U of hexokinase,22 PAN-450, a polymer carrying 450//mol of active ester group/g, was quickly dissolved in... 

Hussain F, Birch DJ, Pickup JC. Glucose sensing based on the intrinsic fluorescence of sol-gel immobilized yeast hexokinase. Analytical Biochemistry 2005, 339, 137-143. 

Determination of ADP and ATP by multiple enzymes in recycling systems pyruvate kinase and hexokinase co-immobilized on aminopropyl CPG, was demonstrated by Kirstein et al. [25]. In addition, a second reactor,with L-lactate dehydrogenase, lactate oxidase, and catalase, was used to increase the sensitivity from 6x 10 5 M with no recycling, to 2 x 10 6 M in the kinase bienzyme reactor,... 

In this method an appropriate enzyme (e.g., GPDase) and the antigen are co-immobilized on a solid phase. Hexokinase-labeled antibody produces an accelerated conversion of glucose, ATP and NAD+ since the enzymes are in each other s vicinity. 

Because of the very high price of ATP, reaction (5.7) must be coupled with a regenerating system, the transfer of phosphate to ADP starting from the enol phosphate of pyruvic acid (an easily accessible and inexpensive phosphate), catalysed by the enzyme pyruvate kinase (reaction (5.8). In the same flask are mixed glucose, phosphoenolpyruvate, hexokinase, pyruvate kinase, and a catalytic quantity of ATP (about 1% mol) and the system produces D-glucose 6-phosphate until the phosphoenolpyruvate runs out. The kinases are easily accessible and, if they are immobilized on an insoluble support (see Section 10.4.1), they are reusable a certain number of times. In this way glucose 6-phosphate can be easily prepared on a 250 g scale (Poliak et al. 1977). 

Commercially available co-immobilized with hexokinase inside a nylon coil... 

The evaluation of a procedure for D-glucose determination using hexokinase and D-glucose 6-phosphate dehydrogenase co-immobilized inside a nylon tube has been reported. The practical and economic feasibility of the system for use in a small laboratory was assessed. 

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