D-Fructose 1,6-diphosphate aldolase

We faced the problem of the poor solubility of most N-protected amino aldehydes in water, which might account for the low reactivity observed with D-fructose-1,6-diphosphate aldolase from rabbit muscle (RAMA) (14, 15, 19-21). Increasing the percentage of organic co-solvent (e.g. dimethylformamide) in the medium to make the aldehyde soluble may lead to either a dramatic enzyme deactivation [22] or an insolubilization of the donor (e.g. dihydroxyacetone (DHA) and DHAP sodium salt). As a result, no reaction or insufficient product yields are often obtained. 

D-Fructose-1,6-diphosphate aldolase (FDP) catalyzes the reversible aldol addition of DHAP and D-glyceraldehyde-3-phosphate (G3P) to form D-fructose-1,6-diphosphate (FDP), for which Keq 10 M in favor of FDP formation (O Scheme 6). Rabbit muscle aldolase accepts a wide range of aldehyde acceptor substrates with DHAP as the donor to generate 35, 45 vicinal diols, stereospecifically (O Scheme 5). A racemic mixture of non-natural aldehyde acceptors can be partially resolved only under conditions of kinetic control. When... 

Aldolases accept a wide range of aldehydes in place of their natural substrates and permit the synthesis of carbohydrates such as azasugars, deoxy sugars, deoxythio sugars, fluoro-sugars, and C8 or C9 sugars. In the case of D-fructose-1,6-diphosphate aldolase (FDP aldolase, Type A), more than 75 aldehydes have been identified as substrates [143]. 

D-Fructose 1,6-diphosphate aldolase has been used to catalyse aldol condensations on some branched-chain sugar derivatives. For example the deoxytetrose (15) afforded the... 

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... 

The essentially nonreversible formation of D-fructose 1-phosphate in the muscle-aldolase system is probably attributable to thermodynamic stabilization. D-Fructose 1-phosphate can form a stable pyranose structure, whereas D-fructose 1,6-diphosphate can exist only in the less stable furanose or acyclic forms.72(,) Only when the cleavage products are removed is the monophosphate effectively split under the influence of aldolase. 

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>... 

Von derOsten, C.H., Sinskey, A.J., Barbas El, C.F., Pederson, R.L., Wang, Y.F. and Wong, C.H., Use of a recombinant bacterial fructose-1,6-diphosphate aldolase in aldol reactions preparative syntheses of 1-deoxynojirimycin, 1-deoxymannojirimycin, l,4-dideoxy-l,4-imino-D-arahinitol, and fagomine. J. Am. Chem. Soc., 1989, 111, 3924. 

Enzymes catalyzing the same reaction but obtained from different sources may have very different properties, but usually operate by the same mechanism, an exception being D-fructose 1,6-diphosphate lyase (aldolase). Caution must, therefore, be observed in correlating mechanistic evidence derived for enzymes from different sources. 

Two new stereocenters are established in the DHAP-dependent aldolases-cata-lyzed carbon-carbon bond formation. Consequently four different stereoisomers can be formed (Scheme 5.23). Enantioselective aldolases that catalyze the formation of just one of each of the stereoisomers are available fructose 1,6-diphosphate aldolase (FDP A), rhamnulose 1-phosphate aldolase (Rha 1-PA), L-fucu-lose 1-phosphate aldolase (Fuc 1-PA) and tagatose 1,6-diphosphate aldolase (TDP A). In particular the FDP A, that catalyzes the formation of the D-threo stereochemistry, has been employed in many syntheses. One such FDP A that... 

Two metabolic patterns are discernible from the results. Carbon atoms 2, 1, and 7 of shikimate (VI) are derived almost equally from G-1,6, G-2,5, and G-3,4, respectively. In the Embden-Meyerhof pathway of hexose metabolism (see Fig. 2), D-fructose 1,6-diphosphate is cleaved to 1,3-dihydroxy-2-propanone phosphate (G-1,2,3) and D-glycerose 3-phosphate (G-4,5,6), and the two trioses are interconverted by triose phosphate isomerase. The observed randomization of label between Cl and C6, C2 and C5, and C3 and C4 of hexose therefore implies that C2, Cl, and C7 of shikimate are derived from a 3-carbon intermediate of glycolysis. The small but significant preponderance of G-6 over G-1, of G-5 over G-2, and, presumably, of G-4 over G-3, can be explained by recent observations that, in the aldolase cleavage of D-fructose 1,6-diphosphate, the 1,3-dihy-... 

Diphosphofructoaldolase is a soluble glycolytic enzyme especially abundant in skeletal muscle, occurring also in the myocardium and to a lesser extent in liver and erythrocytes, so that hemolysis of blood specimens elevates the serum aldolase activity and must therefore be avoided. The molecular weight of muscle aldolase is 147,000-180,000 (DIO), Its function is specifically the reversible splitting of D-fructose-1,6-diphosphate (FDP) into equimolecular amounts of the trioses D-glyceralde-hyde-3-phosphate (G-3-P) and dihydroxyacetone phosphate (DAP). 

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. 

In the actual cleavage reaction of glycolysis, D-fructose< 1,6-diphosphate is converted into D-glyceraldehyde-3-phosphate and dihydroxyacetone, CH2OHCOCH2OH. What kind of reaction is this, basically Sketch out a possible mechanism, neglecting, of course, the all-important role of the enzyme. (Hints The enzyme required is called aldolase. See Problem 21.14, p. 711.)... 

Aldolase (EC 4.1.2.13 D-fructose-l,6-bisdiphosphate D-glyceraldehyde-3-phosphate-lyase ALD) catalyzes the splitting of D-fructose-1,6-diphosphate to D-glyceraldehyde-3-phosphate (GLAP) and dihydroxyacetone-... 

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