Immunoassay glucose oxidase

Chemiluminescence and bioluminescence are also used in immunoassays to detect conventional enzyme labels (eg, alkaline phosphatase, P-galactosidase, glucose oxidase, glucose 6-phosphate dehydrogenase, horseradish peroxidase, microperoxidase, xanthine oxidase). The enhanced chemiluminescence assay for horseradish peroxidase (luminol-peroxide-4-iodophenol detection reagent) and various chemiluminescence adamantyl 1,2-dioxetane aryl phosphate substrates, eg, (11) and (15) for alkaline phosphatase labels are in routine use in immunoassay analyzers and in Western blotting kits (261—266). 

The oxidation reactions of luminol and lucigenin can be used to assay for H Oj. For example, analysis of glucose in biological systems can be achieved using a three-enzyme system of mutarotase, glucose oxidase and horseradish peroxidase by correlation with the amount of HjOj released. Similarly, cholesterol can be measured using cholesterol oxidase. The fact that the rate of luminol oxidation depends on the concentration of the catalyst can be used as a method for determination of Co +, Fe +, Cr + and Mn + and other catalysts.Some examples of the use of luminol, isolumi-nol and their derivatives in immunoassays are shown in Table 3.11. ... 

On the other hand, the main types of immunoassays that can be performed by using labelled antibodies or antigens are direct sandwich, competitive and indirect assays. The labels can be enzymes (alkaline phosphatase, peroxidise or glucose oxidase) metal NPs (gold) fluorescent or electrochemiluminescent probes. 

Chemiluminescence immunoassay methods have many applications (Weeks, 1992). Highly sensitive chemiluminescent immunoassays were developed by Tsuji et al. (1989) for determination of enzymes (oxidases, peroxidase, glucose oxidase, P-D-galactosidase) as well as various hormones and drugs in biological fluids (Tsuji et al., 1989). 

A6. Arakawa, H., Maeda, M., and Tsuji, A., Chemiluminescence enzyme immunoassay of 17a-hydroxyprogesterone using glucose oxidase and bis(2,4,6-trichlorophenyl) oxalate-fluorescent dye system. Chem. Pharm. Bull. 30, 3036-3039 (1982). 

The direct detection of electrochemical labels entails problems with sensitivity. For this reason the majority of electrochemical immimoassay development has focused on the measurement of enzyme labels by detection of eiectroactive products arising from enzyme catalyzed reactions. A wide variety of enzyme labels have been used for electrochemical immunoassays. These include glucose oxidase, glucose-6-phosphate dehydrogenase and alkaline phosphatase. ... 

Fig. 8.4. Schematic illustration of the principle of the separation-free, amperometric enzyme channelling immunoassay with immobilized glucose oxidase and antibody on the PEI-modified electrode surface.

S108 Morris, D.L. (1985). Effect of antibodies to glucose oxidase in the apoenzyme reactivation immunoassay system. Anal. Biochem. ISl, 235-241. 

Suzawa T, Ikaiiyama Y, Aizawa M (1994) Multilabeling of ferrocenes to a glucose oxidase-digoxin conjugate for the development of a homogeneous electroenzymatic immunoassay. Anal Chem 66 3889-3894... 

ADP AFP ab as ALAT AP ASAT ATP BQ BSA CEH CK CME COD con A CV d D E E EC ECME EDTA EIA /e FAD FET FIA G GOD G6P-DH HBg HCG adenosine diphosphate a-fetoprotein antibody antigen alanine aminotranferase alkaline phosphatase aspartate aminotransferase adenosine triphosphate benzoquinone bovine serum albumin cholesterol ester hydrolase creatine kinase chemically modified electrode cholesterol oxidase concanavalin A coefficient of variation (relative standard deviation) layer thickness diffusion coefficient enzyme potential Enzyme Classification enzyme-chemically modified electrode ethylene diamine tetraacetic acid enzyme immunoassay enzyme loading factor flavin adenine dinucleotide field effect transistor flow injection analysis amplification factor glucose oxidase glucose-6-phosphate dehydrogenase hepatitis B surface antigen human chorionic gonadotropin... 

Kuhlmann WD, Peschke P (1986) Glucose oxidase as label in histological immunoassays with enzyme-amplification in a two-step technique coimmobilized horseradish peroxidase as secondary system enzyme for chromogen oxidation. Histochemistry 85 13-17. 

The response of a surface antigen-antibody reaction can also be mediated by an electron transfer reagent. This has been demonstrated by Robinson et al. in their studies on electrochemical immunoassays for hCG and thyroxine. In the analysis of hCG, a two-site amperometric immunoassay was developed in which monoclonal capture antibodies were immobilised on the surface of a glassy carbon electrode. A second antibody against hCG was labelled with glucose oxidase. The electrode was used both to separate free from bound enzyme-antibody conjugate and to assay the enzyme activity electrochemically by use of dimethylaminomethyl ferrocene as an electron transfer mediator. This method was found to correlate well with an immunoradiometric assay. In the analysis of thyroxine, another ferrocene derivative, namely ferrocenemonocarboxylic acid, was used as the electron transfer mediator. ... 

A variation of the EMIT is the apoenzyme reconstruction immunoassay system, where the analyte is coupled not to the enzyme itself but to a cofactor or prosthetic group that is required for enzyme activity. For example, the analyte may be coupled to flavin-adenine dinucleotide (FAD), which is required for glucose oxidase activity. The antibody binds to the FAD-analyte conjugate and prevents FAD from interacting with the enzyme, whose activity is consequently reduced. The more analyte present in the sample, the more competition there is for the antibody and the more FAD-analyte conjugate remains free in solution and available to the enzyme. Again, the level of enzyme activity is related to the quantity of analyte in the sample. 

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