Glucose assays

Another common procedure which is used for glucose assay is the hexokinase procedure in which the glucose is phosphory-lated by means of ATP and then dehydrogenated with glucose-6-phosphate dehydrogenase measuring the abosrption of NADPH... 

Takahara, R. Sasaki, M. Tomisek. A. J. and Natelson, S. Sensitive o-Toluidine reagent for glucose assay at moderately elevated temperatures. Microchem. J. (1974), 19, 319 - 329. 

Oxalate does not interfere with glucose assays, but insulin values determined in oxalate-plasma are lower than those obtained with lithium heparin-plasma or serum (L6). Specimens collected in EDTA demonstrate lower carbon dioxide combining power than those observed with serum or heparin or potassium oxalate plasma (Zl). 

Megazyme, Glucose assay procedure, Megazyme International Ireland Ltd., Bray, Wicklow, Ireland (http //www.megazyme.eom/p range2.asp Submit.x=52 Submit.y=12 search=glu-cose tag35). 

Mix glucose determination reagent concentrate (Total Starch Assay Kit or Glucose Assay Kit Megazyme International Ireland) with 1 liter of lx phosphate buffer (see recipe). Store in aliquots, protected from light, for 3 months at 2° to 5°C or >1 year at -20°C. 

Marbach R, Koschinsky T, Gries FA, Heise HM. Noninvasive blood glucose assay by near-infrared diffuse reflectance spectroscopy of the human inner lip. Applied Spectroscopy 1993,47, 875-881. 

Polyelectrolyte multilayer microspheres, prepared by alternating adsorption of dextran sulfate and protamine on melamine formaldehyde cores followed by the partial decomposition of the core, were used to immobilise the peroxidase and glucose oxidase. Retention of enzymic activity of the peroxidase/glucose oxidase system incorporated into the microspheres was demonstrated. These bienzyme system immobilised in the microspheres can be applied for kinetic glucose assays [ 156]. 

Glycolated CPMV as a [102] tool for cellular recognition and signaling events (glucose assay and hemagglutination)... 

To aleviate the dissolution of the enzymatic film during the glucose assay procedure, a covering membrane made by addition of 10 pi of Nafion 0.5% was used. The amperometric current increases until a constant value of 20 pA is reached on the fourth glucose assay (Fig. IB). The addition of Nafion film atop of the AQ-enzyme layer doesn t seem to denaturate the enzyme entrapped in the AQ film because the current reached a similar value as the current observed in absence of Nafion. On the other hand, the use of Nafion as covering membrane gives a thicker film that leads to mass transport limitation of the substrates in the AQ film (20). It results in a longer time to obtain the steady-state current. 

Acid hydrolysates were added to a low aroma intensity white wine (ie the base wine), and the aroma properties of these samples were assessed by sensory descriptive analysis. In addition, the glycoside isolates from the Australian vineyards were subjected to glycoside hydrolase enzyme treatment, and duo-trio difference tests were performed on these hydrolysates added to a base wine. The volatile composition of each of the hydrolysates was investigated by GC/MS, and relationships between the two sets of data were determined. Finally, the glycoside concentration of each of the juices and skin extracts was determined by the glycosyl-glucose assay. 

Figure 2-19. Absorbances observed with increasing amounts of glucose assayed by the Park and Johnson procedures.

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