Gluconic 2-keto

Ameyama M. 1982. Enzymatic microdetemtination of D-glucose, D-fructose, D-gluconate, 2-keto-D-gluconate, aldehyde, and alcohol with memhrane-hound dehydrogenases. Meth Enzymol 89 20-29. 

The principal organic acids in grape are L(+)-tartaric, L(—)-malic, shikimic and citric acid. Gluconic, 2-keto-D-gluconic and mucic acids are present in rot grapes as metabolites of Botrytis Cinerea. The structures of these compounds are reported in Figure 1.2. 

Additional information <1> (<1> no substrate 2-deoxy-D-ribose, 2-deoxy-D-glucose, o-gluconate, 2-keto-D-gluconate, 2-oxoglutarate, 2-oxo-3-deoxy-6-phosphogluconate [2]) [2]... 

Keto-2-gluconic Diketo-2,5-gluconic Keto-5-fructose Xylosone acid acid... 

Diketo-gluconic acid (24) 2-Keto-L-gulonic acid (2-KGA)... 

The 2-keto-3-deoxy-aldonic acid (phosphate) aldolases from Pseudomonas strains - 3-deoxy-2-keto-L-arabonate (F.C 4.1.2.18), 3-deoxy-2-keto-D-xylonate (EC 4.1.2.28), 3-deoxy-2-keto-6-phospho-D-gluconate (EC 4.1.2.14) and 3-deoxy-2-keto-6-phospho-D-galactonate aldolase (EC 4.1.2.21) - appear to be specific even for the acceptor components, but allow stereoselective syntheses of the respective natural substrates29. 

Figure 10.11 Aldol reactions catalyzed in vivo by the 2-keto-3-deoxy-6-phospho-o-gluconate and 2-keto-3-deoxy-6-phospho-o-galactonate aldolases.

Oxidation of Isopropylidene Derivatives of Ketose Sugars. Whenever isopropylidene derivatives can be obtained in which all groups except the primary alcoholic grouping at Cl are blocked this method is undoubtedly the best. It may be illustrated by reference to the preparation of 2-keto-D-gluconic acid from D-fructose.14... 

The process of lactonization and enolization of 2-keto esters under the influence of alkaline reagents has also been applied to the production of analogs of L-ascorbic acid containing a six-membered ring structure.22 For example, methyl 3,4,6-trimethyl-2-keto-D-gluconate (XLI) is treated... 

There is good evidence for the presence of a five-membered ring in D-araboascorbic acid (XXXIX). This analog of L-ascorbic acid, prepared by method 2 (page 87) from methyl 2-keto-D-gluconate shows the same chemical properties and the same absorption characteristics as L-ascorbic acid. Titration of XXXIX with diazomethane affords, as in the case of L-ascorbic acid, a 3-methyl derivative LXXXII which upon further action with diazomethane gives rise to the 2,3-dimethyl-D-arabo-ascorbic acid (LXXXIII)3 ... 

Moreover, the compound (LV) obtained from the reaction of 2-keto-D-gluconic acid with o-phenylenediamine28 has been dehydrated to give a compound which Maurer erroneously described as LYI. In this case, also, the process of dehydration has been shown to be equivalent to that just described for compound L. The product obtained by interaction of 2-furyl-... 

D-arabino-Hexuionic acid ( 2-Keto-D-gluconic acid ) O H H HO hoh2 c—c—c—c—c—c ooh HO HO H red seaweed, Chondrus crispus ( )... 

Glucuronate and galacturonate are isomeric forms of 0HC(CH0H)4C02. d5-Keto-D-gluconate is HOzCCCHOHLCOCOj. 

Phospho-2-keto-3-deoxygluconate aldolase, an enzyme in the Entner-Doudoroff pathway, that catalyzes the cleavage 6-phospho-2-keto-3-deoxy-D-gluconate to form pyruvate and D-glyceraldehyde 3-phosphate. 

This enzyme [EC 1.1.1.127], also known as 2-keto-3-deoxygluconate dehydrogenase, catalyzes the reaction of 2-dehydro-3-deoxy-D-gluconate with NAD to produce (4S)-4,6-dihydroxy-2,5-dioxohexanoate and NADH. The enzyme isolated from Pseudomonas can utilize NADP as the coenzyme whereas the enzymes isolated... 

The first such case was concerned with the limited substrate acceptance of d-2-keto-3-deoxy-6-phospho-gluconate (KDPG) aldolase (161). This catalyzes the (reversible) reaction of pyruvate (41) to certain chiral aldehydes such as 42, with formation of aldol products such as 43. It was known that this aldolase is highly specific for chir l-phosphorylated aldehydes with the d configuration at the C2 position leading stereoselectively to a precursor of the corresponding d sugar such as 44 (162) ... 

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