Fructose 1,6-diphosphate , synthesis

Enzyme poisons have been studied mainly in attempts to understand the normal physiological processes. As would be expected, synthesis and accumulation of sucrose have often been drastically lowered. In particular, the inhibition of the formation of D-fructose diphosphate and the conversion of D-glucose into D-fructose inhibited the formation of sucrose.288 330... 

SB Sobolov, A Bartoszko-Malik, TR Oeschger, MM Montelbano. Cross-linked enzyme crystals of fructose diphosphate aldolase development as a biocatalyst for synthesis. Tetrahedron Lett 35 7751-7754, 1994. 

Other novel enzymatic examples include the synthesis of cyclic imine saccharides through the use of the fructose diphosphate aldolase (114). This enzyme has also been used for the synthesis of bicyclic carbohydrates... 

A close inspection of Fig. 1 will reveal that in the anaerobic breakdown of glucose to pyruvic acid a total of four energy-rich ( ) bonds are synthesized. However, of these four bonds, one bond is utilized in the primary phosphorylation step of glucose glucose-6-phosphate, and a second is consumed at the fructose-6-phosphate fructose diphosphate level. Hence a net synthesis of only two bonds is realized. 

When either starch or glycogen is utilized, the same number of bonds are formed as with glucose but since the bond energy of the gluco-sidic link of the polysaccharide is preserved by phosphorolysis in the phosphate bond of glucose-l-phosphate, the only bond utilized is at the fructose-6-phosphate fructose diphosphate level. A net synthesis of three is thus observed. 

Pyruvate kinase (PK) is one of the three postulated rate-controlling enzymes of glycolysis. The high-energy phosphate of phosphoenolpyruvate is transferred to ADP by this enzyme, which requires for its activity both monovalent and divalent cations. Enolpyruvate formed in this reaction is converted spontaneously to the keto form of pyruvate with the synthesis of one ATP molecule. PK has four isozymes in mammals M, M2, L, and R. The M2 type, which is considered to be the prototype, is the only form detected in early fetal tissues and is expressed in many adult tissues. This form is progressively replaced by the M( type in the skeletal muscle, heart, and brain by the L type in the liver and by the R type in red blood cells during development or differentiation (M26). The M, and M2 isozymes display Michaelis-Menten kinetics with respect to phosphoenolpyruvate. The Mj isozyme is not affected by fructose-1,6-diphosphate (F-1,6-DP) and the M2 is al-losterically activated by this compound. Type L and R exhibit cooperatively in... 

Brockamp, H.P, Kula, M.R. and Goetz, F. (1991) A robust microbial fructose-1,6-diphosphate aldolase its manufacture and use in sugar synthesis. DE3940431. 

I, 7-diphosphate.170 1 (f> This tetrose phosphate is involved with phosphoenol pyruvate in the formation of shikimic acid via 3-deoxy-2-keto-D-ara6ino-heptonic acid 7-phosphate and, hence, of aromatic compounds.170(d) A synthesis of the tetrose phosphate has been described.170 1 Aldolase shows a high affinity for the heptulose diphosphate and, compared with that for D-fructose 1,6-diphosphate, the rate of reaction is about 60 %. The enzyme transaldolase, purified 400-fold from yeast, catalyzes the following reversible reaction by transfer of the dihydroxyacetonyl group.l70(o>... 

Chenevert R, Dasser M (2000) Chemoenzymatic synthesis of the microbial elicitor (—)-syringolide via a fructose 1,6-diphosphate aldolase-catalyzed condensation reaction. J Org Chem 65 4529 1531... 

Fig. 24 (a, b) Chemo-enzymatic process for synthesis of tetrahydroxylated pyrrolizidines 1-epi-alexine, australine and 3-epi-australine utilising dihydroxyacetone phosphate (DHAP), stereospecific aldol reaction catalysed by fructose-1.6-diphosphate aldolase (FDPA) and acid phosphatase (Pase) [149]... 

Scheme 5.12. Synthesis of D- and L-fractose catalyzed by fructose 1,6-diphosphate and rham-nulose 1-phosphate aldolases. P = PO32. ...

Fig. 3.—The Enzymic Synthesis of D-ai(ro-Heptulose 1,7-Diphosphate from d-Fructose 1,6-Diphosphate and n-offro-Heptulose 7-Phosphate.

The conversion, by bacterial extracts, of D-oZtro-heptulose 1,7-diphosphate to shikimate, essentially without side reactions, greatly facilitated subsequent study of the intermediate steps in the synthesis. It was shown that the addition of iodoacetate or fluoride completely blocks this conversion. In the presence of iodoacetate, synthesis is restored by the addition of either D-glyceronic acid 3-phosphate or enolpyruvate phosphate. In the presence of fluoride, only enolpyruvate phosphate is able to restore shikimate synthesis. Neither D-fructose 1,6-diphosphate nor pyruvate reverses these inhibitions. These results suggested that the reactions of glycolysis, from triose phosphate to enolpyruvate phosphate (see Fig. 2), are involved in the conversion of D-oZfro-heptulose diphosphate to shikimate. The effect... 

Figure 20.13. Synthesis of Sucrose. Sucrose 6-phosphate is formed by the reaction between fructose 6-phosphate and the activated intermediate uridine diphosphate glucose (UDP-glucose).

Bischofberger, N, Waldmann, H, Saito, T, Simon, E S, Lees, W, Bednarski, M D, Whitesides, G M, Synthesis of analogues of 1,3-dihydroxyacetone phosphate and glyceraldehyde 3-phosphate for use in studies of fructose-1,6-diphosphate aldolase, J. Org. Chem., 53, 3457-3465, 1988. 

Although many aldolases have been characterized for research purposes, these enzymes have not been developed commercially to any significant extent. This is likely due to the availability of the various biocatalysts and the need for dihydroxyacetone phosphate (DHAP) (44), the expensive donor substrate required in nearly all aldolase reactions. A number of chemical and enzymatic routes have been described for DHAP synthesis, which could alleviate these concerns [12], In terms of the enzyme supply issue, this may change with the introduction of products from Boehringer Mannheim and their Chirazyme Aldol reaction kit. They have three kits, each containing a different aldolase fructose-1,6-diphosphate FruA) (EC 4.1.2.13), L-rhamnulose-1-phosphate RhuA (EC 4.1.2.19), and L-fuculose-1-phosphate (FucA) (EC 4.1.2.17). As more screening... 

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