3-Keto gluconate 6-phosphate

In this organism, the product of oxidation of glucose-6-phosphate and of the phosphorylation of gluconate has been demonstrated to be 6-phos-phogluconate. This substance, as will be discussed below, is oxidized and is decarboxylated with the loss of the first carbon, Ci, to form the keto-pentose phosphate, ribulose-5-phosphate (Fig. 11 A). The loss of this car-... 

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. 

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. 

Matzerath, I., W. Klaui, R. Klasen, and H. Sahm. 1995. Vanadate catalyzed oxidation of 5-keto-D-gluconic acid to tartaric acid The unexpected effect of phosphate and carbonate on rate and selectivity. Inorg. Chim. Acta 237 203-205. 

Bromate, chloride, bromide, nitrite, nitrate, hypophosphite (HP022 ), selenite, selenate, sulphate, phosphate, pyrophosphate, arsenate, chromate, a-hydroxybutyrate, butyrate, formate, acetate, glycolate, gluconate, valerate, a-hydroxy valerate, pyruvate, monochloroacetate, dichloroacetate, trifluoroacetate, galactonurate, gluconurate, a-keto-glutarate, oxalate, fumarate, phthalate, oxalacetate, citrate, isocitrate, cis aconitate, trans aconitate, succinate, maleate, malonate, quinate, tartrate, hexane sulphonate, octane sulphonate, octane sulphate, decane sulphonate, dodecane sulphonate and dodecane sulphate... 

Other pyruvate- and phosphoenolpyruvate-dependent aldolases have been isolated and purified, but have not yet been extensively investigated for synthetic use. Those showing promise for future applications include, 3-deoxy-D-arabino-2-heptulosonic acid 7-phosphate (DAHP) synthetase (EC 4.1.2.15), 2-keto-4-hydroxyglutarate (KHG) aldolase (EC 4.1.2.31), and 2-keto-3-deoxy-D-gluconate (KDG) aldolase (EC 4.1.2.20). DAHP synthetase has been used... 

Decarboxylation of 3 keto l-gluconate 6-phosphate (KGPDS activity, 2.3 x 10 )... 

Several other pathways of glucose catabolism have been discovered in different microorganisms. In Pseudomonas saccharophila it was observed (100) that D-gluconic acid 6-phosphate was degraded to pyruvic acid and triose phosphate. It was postulated that an intermediate 2-keto-3-deoxy-D-gluconic acid 6-phosphate was formed. Subsequently this intermediate was isolated and characterized (101). The following pathway was suggested. 

Bacteria often use the Meyerhof sequence, but at least two alternative pathways have been found. In one of these (the pentose phosphate pathway) glucose-6-phosphate is oxidized to ribulose-5-phosphate, two molecules of which are quickly changed to one molecule each of glyceraldehyde-3-phosphate and sedoheptulose-7-phosphate. These phosphates then yield fructose-6-phosphate and a tetrose phosphate. In the other (the 2-keto-3-deoxy-6-phosphogluconate pathway), glucose is oxidized to gluconate by a primitive route without prior phosphorylation. The non-Meyerhof routes are favoured by those bacteria, such as the pseudomonads and aerobacters, which cannot utilize glucose-6-phosphate. 

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