Dihydroxy acetone phosphate

This cleavage is a retro aldol reaction It is the reverse of the process by which d fruc tose 1 6 diphosphate would be formed by aldol addition of the enolate of dihydroxy acetone phosphate to d glyceraldehyde 3 phosphate The enzyme aldolase catalyzes both the aldol addition of the two components and m glycolysis the retro aldol cleavage of D fructose 1 6 diphosphate... 

Figure 17.8 The biologi-cal oxidation of an alcohol (sn-glycerol 3-phosphate) to give a ketone dihydroxy-acetone phosphate). This mechanism is the exact opposite of the ketone reduction shown previously in Figure 17.4.

Of the known classes of aldolase, DERA (statin side chain) and pyruvate aldolases (sialic acids) have been shown to be of particular value in API production as they use readily accessible substrates. Glycine-dependent aldolases are another valuable class that allow access to p-hydroxy amino acid derivatives. In contrast, dihydroxy acetone phosphate (DHAP) aldolases, which also access two stereogenic centres simultaneously,... 

Metabolism of Glycerol Glycerol obtained from the breakdown of fat is metabolized by conversion to dihydroxy-acetone phosphate, a glycolytic intermediate, in two enzyme-catalyzed reactions. Propose a reaction sequence for glycerol metabolism. On which known enzyme-catalyzed reactions is your proposal based Write the net equation for the conversion of glycerol to pyruvate according to your scheme. 

The catabolism of L-fucose by E. coli requires cleavage of L-fuculose-l-phosphate to form dihydroxy-acetone phosphate and D-lactaldehyde by a class II aldolase.193... 

TPI, another glycolytic enzyme that catalyzes the interconversion of dihydroxy-acetone phosphate (DHAP) and D-glyceraldehyde-3-phosphate in glycolysis, was also oxidatively modified [32, 63, 66]. However, no change of TPI activity was observed [66], probably because the carbonyl groups added were localized away from the catalytic site of this enzyme. TPI was strongly inhibited by endogenous... 

Dicyclohexylcarbodiimide Dihydroxy acetone phosphate Deoxyribonucleic acid Complementary DNA Deoxyribonuclease Dinitrophenol L-Dihydroxyphenylalanine 2,3-Diphosphoglycerate Ethylenediaminetetraacetic acid Eicosapentaenoic acid Endoplasmic reticulum Fatty add... 

The glycerol ethers and plasmalogens are a unique class of phosphoglycerides that contain an ether-linked chain at the sn-1 position. These are formed by the incorporation of acyl CoA at the sn-1 position of dihydroxy-acetone phosphate. The acyl group is then exchanged for a long-chain... 

Primary amine catalysis (usually involving a lysine residue) has been recognised to play an important role in various enzyme-catalysed reactions. Examples are the conversion of acetoacetate to acetone catalysed by acetoacetate decarboxylase, the condensation of two molecules of S-aminolevulinic acid catalysed by -aminolevulinic deshydratase during the biosynthesis of porphyrins, and the reversible aldol condensation of dihydroxy-acetone phosphate with glyceraldehyde which in the presence of aldolase yields fructose-1-phosphate (64) (For reviews see, for example, Snell and Di Mari,... 

The glycerol 3-phosphate traverses the mitochondrial membrane and is then oxidized back to dihydroxy-acetone phosphate by the mitochondrial enzyme ... 

Fructose-6-phosphate formed from the isomerization discussed above is further phos-phorylated during glycolysis to fructose-1,6-diphosphate (108), which is then cleaved by fructose-1,6-bisphosphate aldolase to afford dihydroxy acetone phosphate (109) and glyceraldehyde-3-phosphate (110). This cleavage reaction is the reverse of an aldol condensation discussed in Section II.C and during gluconeogenesis. In the latter case, fructose-1,6-bisphosphate aldolase catalyzes the reverse reaction herein via aldol condensation of the ketose 109 and the aldose 110 to form linear fructose-1,6-bisphosphate (108) . 

In most plants, the major products of photosynthesis are starch (formed in chloroplasts and sucrose (formed in the cytosol). Both of these products (collectively called photosynthate) are formed from photosynthetically generated dihydroxy-acetone phosphate (DHAP) via pathways that in some respects are similar to the gluconeogenic pathway of animal cells. In the first case, DHAP is converted to hexose phosphates, which, in turn, are converted to starch within the chloroplast. In sucrose synthesis, DHAP (or a derivative) is transported to the cytosol and there it is converted to sucrose. 

A more recently discovered second pathway starts from ribulose 5-phosphate (49) that is condensed with ammonia and glyceraldehyde phosphate or its isomerization product dihydroxy-acetone phosphate (50), which affords pyridoxal 5 -phosphate in a single enzyme-catalyzed reaction step (Fig. 5B) (28, 29). This pathway seems to be widely distributed it is used in plants (30) and has also been shown to proceed in fungi, archaea, and most eubacteria. 

The addition of functional groups to double bonds or the removal of groups to form double bonds constitutes the final class of reactions. The enzymes that catalyze these types of reaction are classified as lyases (Section 8.1.3). An important example, illustrated in reaction 7, is the conversion of the six-carbon molecule fructose 1,6-bisphosphate (F-1, 6-BP) into 2 three-carbon fragments dihydroxy acetone phosphate and glyceraldehyde 3-phosphate. 

Hexose-triose equilibrium. What are the equilibrium concentrations of fructose 1,6-bisphosphate, dihydroxy acetone phosphate, and glyceraldehyde 3-phosphate when 1 mM fructose 1,6-bisphosphate is incubated with aldolase under standard conditions ... 

When 2-azidoaldehydes are used as substrates in the RAMA-catalyzed aldol reaction with dihydroxy acetone phosphate (DHAP), the azidoketones thus obtained can be reduced into the corresponding primary amines. Subsequent equilibration to imine intermediates, followed by reduction, generates the corresponding pyrrolidines (Scheme 13.16) [22,33]. 1,4-Dideoxy-1,4-imino-D-arabinitol 11 was prepared from azidoacetaldehyde. Both 2R,5R) and 2S,5R)-bis(hydroxymethyl)-(3R,4R)-dihydroxypyrrolidine (12 and 13) were derived from racemic 2-azido-3-hydroxypropanol. The aldol product resulting from kinetic control was converted into the (2R,2R) derivative 12, whereas the product resulting from thermodynamic control gave the... 

Enzyme mechanisms can often avoid high-energy, unstable cationic or anionic intermediates that increase the reaction barrier. Triosephosphate isomerase catalyzes the tautomerization of the achiral dihydroxy acetone phosphate (DHAP) to f -glyceraldehyde-3-phosphate (G3P) by the mechanism shown below. Not only does the push-pull mechanism avoid forming a highly basic enolate, but the binding mode of DHAP determines which face of the enediol will be protonated in the second step, and therefore... 

Supplementation with dihydroxy acetone phosphate could provide a glycolytic substrate without the risk of hyperuricemia. 

---