Glycolysis intermediates

Glycogen content phosphoryla tion Low phosphorylation glycolysis Intermediate High... 

Table 9.1 Evaluation of glycolysis intermediates as substrates for DR5P production by deoxyriboaldolase-expressing E. coli without and with ATP.

Aromatic compounds arise in several ways. The major mute utilized by autotrophic organisms for synthesis of the aromatic amino acids, quinones, and tocopherols is the shikimate pathway. As outlined here, it starts with the glycolysis intermediate phosphoenolpyruvate (PEP) and erythrose 4-phosphate, a metabolite from the pentose phosphate pathway. Phenylalanine, tyrosine, and tryptophan are not only used for protein synthesis but are converted into a broad range of hormones, chromophores, alkaloids, and structural materials. In plants phenylalanine is deaminated to cinnamate which yields hundreds of secondary products. In another pathway ribose 5-phosphate is converted to pyrimidine and purine nucleotides and also to flavins, folates, molybdopterin, and many other pterin derivatives. 

Synthesis of Some Physiologically Important Compounds from Glycolysis Intermediates... 

Fructose may be phosphorylated to either fructose-6-phosphate, the glycolysis intermediate, or to fructose-1-phosphate, which may be metabolized by a specific fructose-l-phosphate aldolase ... 

DHAP is a glycolysis intermediate, whereas glyceraldehyde must be reduced by a mitochondrial enzyme, glyceraldehyde dehydrogenase, to glycerol, which is then subject to action by glycerol kinase in the liver. The aldolase seems to be the principal pathway of metabolizing fructose and depends on the initial phosphorylation step catalyzed by fructokinase, which produces fructose-l-phosphate. Fructokinase is defective in an inherited disorder, essential fructosuria. Fructose-l-phosphate aldolase is deficient in the hereditary disorder fructose intolerance. 

DHAP, a glycolysis intermediate, is reduced by NADH to glycerol-3-phosphate. Triose isomerase converts it to glyceraldehyde-3-phosphate, and it is a product of the fructose-1-phosphate aldolase reaction. 

Figure 20.11 Conversion of 3-phosphoglyceric acid to serine. 3-Phosphoglyceric acid originates from dihydroxyacetone phosphate, a glycolysis intermediate.

Evaluation of Glycolysis Intermediates as the Substrates for 2-Deoxyriboase 5-Phosphate Production by a Deoxyriboaldolase-Expressing E. coli 10B5/pTS8... 

Different rates for a and 3-glucose translocation flux of carbon through most glycolysis intermediates to end products evaluated a- and 3-fructose biphosphates are in anomeric equilibrium in yeast9 but not in bacterium, aldolose-triose phosphate isomerase triangle is near equilibrium. 

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