Biological oxidation of carbohydrates

Krebs, H.A. (1943). The intermediary stages in the biological oxidation of carbohydrate. Advances in Enzymol. 3, 191-252. 

Next, let us take a look at the overall picture of the biological oxidation of carbohydrates. We start with glycogen ( sugar-former ) the form in which carbohydrates are stored in the animal body. This, we have seen (Sec. 35.9), is a starch-like polymer of D-glucose,... 

The oxidation of carbohydrate involves the making and breaking of C-H bonds. This is a two electron process, and the most efficient way of achieving the oxidation will use a two electron oxidant. In many biological systems one of the key redox steps involves the two-electron conversion of a quinone to a hydroquinone (Fig. 10-6). 

Biological reduction processes in sediments may be viewed as the oxidation of carbohydrate (in its simplest form CH2O) with accompanying reduction of an oxygen carrier. In the first instance, dissolved molecular oxygen is used. The reaction is thermodynamically favoured, as reflected by the strongly negative AG . 

The processes of life also depend on oxidation of organic substrates, whereby metabolic energy is derived from the overall oxidation of carbohydrates, fats, and proteins to carbon dioxide and water, among other products, as illustrated in Equation 16.5. Potentially poisonous substances are commonly detoxified by biological oxidation to more benign substances. Thus, nicotine, which is toxic to humans if present in sufficiently high concentration, is oxidized in the liver to cotinine (Eq. 16.6), a substance of low toxicity. 

In the area of synthesis Garegg has surveyed various regioselective reactions which are applied in oligosaccharide synthesis under the title "Challenges and opportunities for organic synthesis with saccharides of biological importance." More specifically a substantial review has dealt with basic aspects of the major issue of the methods available for the preparation of 1,2-asymmetric centres with defined relative stereochemistry, and 1,3-difunctional compounds in which 1,2-difunctional stereorelationships may also be established. A later publication which builds on this will be of more specific relevance in carbohydrate chemistry. More specific topics to have been surveyed are cycloaddition reactions in carbohydrate chemistry and noble metal-catalysed oxidations of carbohydrates. ... 

Other Processes. Isopropyl alcohol can be prepared by the Hquid-phase oxidation of propane (118). It is produced iacidentaHy by the reductive condensation of acetone, and is pardy recovered from fermentation (119). Large-scale commercial biological production of isopropyl alcohol from carbohydrate raw materials has also been studied (120—123). 

Dorman G (2000) Photoaffinity Labeling in Biological Signal Transduction. 211 169-225 Drabowicz J, Mikolajczyk M (2000) Selenium at Higher Oxidation States. 208 143-176 Eder B, see Wrodnigg TM (2001) The Amadori and Heyns Rearrangements Landmarks in the History of Carbohydrate Chemistry or Unrecognized Synthetic Opportunities 215 115-175... 

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