Dihydroxyacetone monophosphate

Glucose (Glc) is taken up and phosphorylated into glucose-6-phosphate (Glc6P), with consumption of ATP. Isomerization and phosphorylation afford fructose-l,6-bisphosphate (Frul,6P2), which is cleaved into two triose molecules D-glyceraldehyde-3-phosphate (GA3P) and dihydroxyacetone monophosphate (DHAP). These are equilibrated by triose phosphate isomerase as only GA3P is metabolized further, except approximately 5 mol% of DHAP that leaks out of the pathway via reduction to glycerol, which is excreted as a side-product. 

Two potent glycosidase inhibitors, (—)-l-deoxymannonojirimycin (—)-7 and (+)-l-deoxynojiri-mycin (+)-8, are readily obtained in three steps utilizing RAMA as a catalyst in the key C-C bond forming step [22,30]. From racemic 3-azido-2-hydroxypropanal and dihydroxyacetone monophosphate (DHAP), diastereomeric 6-azidoketones are formed. Following the acid phosphatase-catalyzed removal of phosphate and subsequent reductive amination (Scheme 13.15), the products are isolated in a 4 1 ratio favoring the manno derivative. A similar result is obtained with... 

One of the most efficient methods for the generation of 2,5-dideoxy-2,5-iminogalactitol 16 relies on the fuculose-1-phosphate aldolase-catalyzed aldol condensation of 2-azido-3-hydroxypropanal with dihydroxyacetone monophosphate (Scheme 13.17). The same method, applied to (2/ )-2-azidopropanal R)-V7 and to (25 )-2-azido-propanal (5 )-17, allows for the preparation of 2,5,6-trideoxy-2,5-imino-D-allitol 18 and 2,5,6-trideoxy-2,5-imino-L-talitol 19, respectively [22]. 

Again in the first step of the reaction between 1,3-dihydroxyacetone monophosphate (5.41) and glyceraldehyde-3-phosphate catalysed by aldolase to form fructose-1,6-diphosphate or the reverse reaction, a ketimine (5.42) is formed between the substrate and the e-amino group of a Lys residue in the enzyme. The formation of this intermediate (5.42) can be demonstrated similarly by trapping it as a secondary amine using NaBH4 to reduce the ketimine. The glyceraldehyde-3-... 

A number of 6-substituted D-fructose derivatives (including the chlorodeoxy-and deoxyiodo-compounds) have been prepared from the corresponding 3-sub-stituted D-glyceraldehydes using an aldolase and dihydroxyacetone monophosphate. ... 

Compound 3 was prepared from commercially available (/ )-(- -)-5-hy-droxymethyl-5H-furan-2-one by 0-benzylation and subsequent conjugate addition of (PhMe2Si)2 Cu(CN)Li2, and converted to 2-deoxy-L-ribose (5) via the 2-deoxy-L-ribonolactone derivative 4 2 -Deoxy-D-ribose 5-phosphates Relabelled at C-3 and C-4, and/or at C-5, were prepared in a chemoenz3miatic approach by cyclizing appropriately labelled dihydroxyacetone monophosphates with unlabelled acetaldehyde. By use of [ 2]-, or [2- RC]-... 

Scheme 11.5. A cartoon representation of the catalyzed (fructose-bisphosphate aldolase, EC 4.1.2.13) aldol-type condensation between glyceraldehyde 3-phosphate and dihydroxyacetone monophosphate to produce the six-carbon ketosugar fructose-1,6-bisphosphate. An active site lysine Lys-NH2 [" H3NCH2CH2CH2CH2CH(NH3 )C02 ] apparently serves as the catalyst through addition at the carbonyl followed by proton tautomerization.

The erythrose 4-phosphate generated in the same step (Scheme 11.7) as the derivative of thiamine diphosphate is then available for enzyme-catalyzed aldol-type condensation with dihydroxyacetone monophosphate just as shown in Scheme 11.5 for the analogous reaction with glyceraldehyde 3-phosphate and using the same fructose-bisphosphate aldolase (EC 4.1.2.13). 

Scheme 11.10. A representation of the aldol-type condensation of erythrose 4-phosphate with dihydroxyacetone monophosphate using fructose bisphosphate aldolase (EC 4.1.2.13) to produce a seven-carbon sugar, sedoheptulose 1,7-bisphosphate. The enzyme-catalyzed hydrolysis (EC 3.1.3.37) yielding sedoheptulose 7-phosphate is also shown.

The synthesis of glucose (gluconeogenesis), which is then stored as starch (a mixture of a-glucose polymers, vide infra) and/or cellulose (a mixture of P-glucose polymers, vide infra), occurs by condensation of 3-phosphoglyceraldehyde (glycer-aldehyde 3-phosphate) with dihydroxyacetone monophosphate (Scheme 11.13). 

Calvin-Benson-Bassham cycle, a seven-carbon sugar arises from the reaction of dihydroxyacetone monophosphate with erythrose 4-phosphate. 

As shown in Scheme 12.87, D-ribulose-5-phosphate can also be derived from D-glucose-6-phosphate, which, as shown in Scheme 11.13, is generated from dihydroxyacetone monophosphate (i.e., an isomer of 3-phosphoglycerate— from the Calvin cycle). 

Quinolinic acid is generated by one of two different pathways. In one pathway, by utilizing the enzyme quinolinate synthase (EC 1.4.3.16), whose crystal structure has recently been obtained, only the broadest outlines of a possible pathway arising from a reaction between dihydroxyacetone monophosphate and iminoaspartate have been adumbrated (Scheme 12.104),... 

There have been synthesized in this laboratory over the past several years a variety of phosphonic acids which are nominally isosteric with natural monophosphate esters. Of this collection of compounds three are of particular interest for the present work. These are (S)-3,4-dihydroxybutyl-1-phosphonic acid (A)(1), an isosteric analogue of sn-glycerol-3-phosphate 4-hydroxy-3-oxobutyl-l-phosphonic acid (B)( ), an isosteric analogue of dihydroxyacetone phosphate and 5-carboxy-4-hydroxy-4-methylpentyl-l-phosphonic acid (C)(3), an isosteric analogue of 5-phosphomevalonate. 

Evidently, Cs-compounds are utilized via the dikinase reaction (at least with lactate and pyruvate as substrates), gluconeogenetic reactions, hexose monophosphate and diphosphate pathways. It is suggested that glycerol degradation proceeds through the formation of glycerol-3-phosphate and dihydroxyacetone (Stjemholm and Wood, 1963). In cells growing on... 

Figure 2. Biosynthesis of plasmalogens in mammalian tissues. Enzymes (1) dihydroxyacetone phosphate acyltransferase (2) 1-acyldihydroxyacetone phosphate synthase (3) 1-alkyldihydroxyacetone phosphate oxidoreductase (4) l-alkyl-5n-glycero-3-phosphate acyltransferase (5) 1-afkyl 2-acyl-5w-glycero-3-phosphohydrolase (6) CDP-ethanolamine transferase (7) l-alkyl-2-acyl-5w-glycero-3-phosphoethanolamine desaturase (8) methyltransferases and base-exchange enzymes. CDP-ethanolamine, cytidine diphosphoethanolamine. CMP, cytidine monophosphate. CoA, coenzyme A. DHAP, dihydroxyacetone phosphate. NADH, nicotinamide adenine dinucleotide, reduced form. NAD, nicotinamide adenine dinucleotide, oxidized form. Pi, phosphate.

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