Glyceraldehyde phosphate/pyruvate

Disch, A., Schwender, J., Muller, C., Lichtenthaler, H.K., and Rohmer, M., Distribution of the mevalonate and glyceraldehyde phosphate/pyruvate pathways for isoprenoid biosynthesis in unicellular algae and the cyanobacterium Synechocystis PCC 6714, Biochem.., 333, 381, 1998. 

Figure 5.4 Outline of the newly discovered glyceraldehyde phosphate/pyruvate pathway for the formation of C5 isoprenoid units. None of the intermediates after 2-C-methyl-D-erythritol 4-phosphate is known. P indicates a phosphate moiety. TPP, thiamine pyrophosphate NADP, nicotinamide adenine dinucleotide phosphate.

D-glyceraldehyde-3-phosphate, pyruvate (G3P) l-deoxy-D-xylulose-5-phosphate (DXP) 2C-methyl-D-erythritol-4-phosphate (MEP) 4-diphosph-2C-methyl-D-erythritol (CDP-ME) 4-diphosphocytidyl-2C-methyl-D-erythritol-2-phophate (CDP-MEP)... 

Maier, W., B. Schneider et al. (1998). Biosynthesis of sesquiterpenoid cyclohexenone derivatives in mycorrhizal barley roots proceeds via the glyceraldehyde 3-phosphate/pyruvate pathway. Tetrahedron Lett. 39(7) 521-524. 

Tyrosyl-tRNA synthetase dl, d2 Thermolysin dl, d2 T4 phage lysozyme dl, d2 Glucosephosphate isomerase dl, d2 Pyruvate kinase dl, d2 Pyruvate kinase d2, d3 Lactate dehydrogenase dl, d2 Alcohol dehydrogenase dl, d2 Glyceraldehyde-phosphate dehydrogenase dl,d2... 

Terpenes, biogenetically, arise from two simple five-carbon moieties. Isoprenyl-diphosphate (IPP) and dimethylallyldiphosphate (DMAPP) serve as universal precursors for the biosynthesis of terpenes. They are biosynthesised from three acetylcoenzyme A moieties through mevalonic acid (MVA) via the so-called mevalonate pathway. About 10 years ago, the existence of a second pathway leading to IPP and DMAPP was discovered involving l-deoxy-D-xylulose-5-phos-phate (DXP) and 2C-methyl-D-erythritol-4-phosphate (MEP). This so-called non-mevalonate or deoxyxylulose phosphate pathway starts off with the condensation of glyceraldehyde phosphate and pyruvate affording DXP. Through a series of reactions as shown in Fig. 4.1, IPP and DMAPP are formed, respectively [3,7, 42, 43]. 

Figure 22-2 The glyceraldehyde 3-phosphate pyruvate alternative pathway of isoprenoid biosynthesis. The intermediate 1-deoxyxylulose 5-phosphate may enter terpenes, vitamin B6, and thiamin. Isopentenyl diphosphate is shown as the final product, but the intermediate steps are uncertain. See Lange et al 2 ...

Aside from PEPCase, a number of other CAM-related genes have been partially characterised (Table 1). These include cDNA clones for pyruvate, orthophosphate dikinase (PPDK), a specific NADP malate dehydrogenase (MDH), glyceraldehyde phosphate dehydrogenase (GaPDH) and NADP-dependent malic enzyme (MOD). Previous studies indicated that the enzymatic activities of these gene products increased upon salt stress in the ice plant (Holtum Winter, 1982). As in the case... 

A similar conclusion was arrived at by Arnold and Pette ( 2) from studies carried out on the in vitro binding of aldolase glyceraldehyde phosphate dehyrogenase, fructose-6-phosphate kinase, phosphoglycerate kinase, pyruvate kinase and lactate dehydrogenase to the structural proteins F-actin, myosin, acto-myosin and stromaprotein. 

Putra, S.R., Disch, A., Bravo, J.M., and Rohmer, M. (1998). Distribution of mevalonate and glyceraldehyde 3-phosphate/pyruvate routes for isoprenoid biosynthesis in some gram-negative bacteria and mycobacteria. FEMS Microbiol Lett 164 169-175. 

Deoxy-D-xylulose is a known natural product. It was first isolated from the fermentation broth of a Streptomyces and later shown to be a precursor of pyridoxol. Its structure can be deduced biogenetically from pyruvate and glyceraldehyde phosphate (Figs. 2 and 3). Two H-labeled DX isotopomers were synthesized chemically. They were incorporated efficiently into the prenyl chains of ubiquinone and menaquinone by wild-type E. coli, indicating that a DX derivative is an isoprenoid precursor (2, 3). 

Glyceraldehyde 3-phosphate Pyruvate Isocitrate a-Ketoglutarate Malate... 

In bacteria and plastids of plants, formation of prenyl pyrophosphates, which are the precursors of carotenoids, proceeds via an alternative—the glyceraldehyde-3-phosphate pyruvate pathway. The pathway is apparently the sole source of isoprenoid compounds for the unicellular algae Scenedesmus (Metzler 2003). Initially, pyruvate is decarboxylated by a l-deoxyxylulose-5-phosphate synthase and condensed with D-glyceraldehyde 3-phosphate to form 1-deoxyxylulose 5-phosphate. This product may be the branching point for independent routes to isopentyl pyrophosphate (IPP) and dimethylallyl pyrophosphate (DMAPP). 

If the degradation of 1- C-labeUed glucose, e.g. in Escherichia coli or Alicydo-bacillus acidoterrestris, is investigated, the label is found at the terminal carbon atom (C-3) of glyceraldehyde-3-phosphate, pyruvate and acetyl-CoA. 

This molecular complexity is intriguing and must have a physiological meaning. Kaplan and his associates have proposed the following explanation. In skeletal muscle the main function of LDH is to convert pyruvate to lactate for the purpose of oxidizing the NADH generated by glyceraldehyde phosphate oxida-... 

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