2- Ketogluconate

Fumaric acid Itaconic acid Citric acid Kojic acid 2-Ketogluconic acid 5-Ketogluconic acid Gluconic acid Mannitol ... 

Isatis chinensis (Thunb.) Nakai I. chinensis (Thunb.) Nakai var. graminifoba (Ledeb.) H. C. Fu I. tinctoria L. Ban Lan Gen (leaf, root) Quercetin, kaempferol, stachyose, manneotetrose, lupeose, cicerose, isatan, indoxyl-5-ketogluconate.50 Antiviral, antibacterial, increase blood flow, improve microcirculation, lower blood pressue. 

Isatis tinctoria L. China Quercetin, kaempferol, stachyose, manneotetrose, lupeose, cicerose, isatan, indoxyl-5-ketogluconate.50 Antiviral, antibacterial, increase blood flow, improve microcirculation, lower blood pressure. 

In contrast to gluconic acid, 5-ketogluconic acid (VIII) is readily transformed into methyl 5-formylfuroate (IX) in almost quantitative... 

Oxidation of ETOH Overoxidation of acetic acid Oxidation of lactate Oxidation of glyceror (ketogenesis) Water-soluble brown pigments on GYC 5-ketogluconic acid ... 

Speciation of A. aceti and A. pasteurianus requires the ability to detect oxidation of glycerol to dihydroxyacetone, a property called ketogenesis (see Procedure 2.3.4), as well as the formation of 5-ketogluconic acid from D-glucose. Table 2-4 summarizes expected results for the three important species. 

Datta, A.G. and H. Katznelson. 1957. Oxidation of 2,5-ketogluconate by a cell-free extract from Acetobacter melanogenum. Nature (London) 179 153-154. 

De Ley, j. 1958. Pathways of 5-ketogluconate catabolism in bacteria. Biochim. Biophy. Acta 27 652-653. 

Okamoto, K. 1963. Enzymatic studies on formation of 5-ketogluconic acid. II. 5-Ketogluconate reductase. J. Biochem. (Tokyo) 53 448-450. 

Gluconate yields 2,5-ketogluconate. a-Ketobutyrate yields glycine. 

Ketogluconic acid has been isolated from a polysaccharide occurring in Irish moss 119), but no other similar product has been found in nature. Both 2-keto- and 5-ketogluconic acids have been prepared by the action of bacteria. Pyruvic acid and a-ketoglutaric acid (Chapter XIII) are also keto acids. 

Ketogluconic acid in sirupy form is unstable, turns black in a short time, and froths with the liberation of gas 135). 

More drastic oxidation of aldoses with hypoiodite leads to keto acids and finally to cleavage of carbon-carbon bonds. Honig and Tempus 199) claimed to have oxidized glucose stepwise to gluconic acid, 2-ketogluconic acid, and n-arabonic acid. However, other workers claim that the main product is 5-ketogluconic acid 200),... 

Acetobacter suboxydans may oxidize glucose to 5-ketogluconic acid (283). Gluconic acid is formed initially and only subsequently is converted to the... 

Acetobacter and Pseudomonas strains readily convert glucose to gluconate, and this substance is then oxidized to 2-ketogluconate or to 5-ketogluconate. These substances may be distinguished by the ability of 2-keto acids to form spectrophotometrically detectable quinoxalines. 5-Ketogluconate reduces Benedicts reagent at 25 C. The marked reactivity of the latter presumably... 

Some Acetobacter strains produce predominantly the 5-ketogluconate which has been used commercially in the synthesis of isoascorbic acid. The production by Acetobacter of a soluble reducing acid which is neither the 2- nor the 5-keto acid has also been reported. It is possible that this... 

---