Answer to Question #124819 in Biochemistry for Sreelakshmi

Question

4. a. In a procedure for testing blood glucose, a drop of blood is placed on a paper strip impregnated with the enzyme glucose oxidase and all the reagents necessary for the reaction.
The H2O2 produced causes a color change on the paper that indicates how much glucose is present. Since glucose oxidase is specific for the beta anomer of glucose and doesn’t act on alpha anomer, in spite of this specificity, the reaction is used in clinical assay for measuring total blood glucose which consists of a mixture of beta D glucose and alpha D glucose. Explain how this assay is effective in measuring total blood glucose?

Answer 1

The alpha and beta anomers of glucose are in equilibrium with the linear for and with each other. During the oxidation of beta-glucose causes the formation of D-gluconic acid. As a result, the concentration of beta-glucose decreases, the equilibrium shifts, and alpha glucose is transformed into beta-glucose. Therefore, all alpha glucose is converted to beta-glucose that is measured in the glucose oxidase assay.