Aldolases fructose 1,6-diphosphate aldolase

Glyceraldehyde phosphate and dihydroxyacetone phosphate react in the presence of aldolase to yield fructose diphosphate as the only product under physiolocial conditions. 

Scheme 1 Reversible aldol addition reaction catalyzed by fructose diphosphate aldolase.

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. 

Scheme 5.1. The two types of aldolase mechanisms The type I Schiff-base forming aldolase is represented by rabbit muscle fructose disphosphate (FDP) aldolase (RAMA, top), and the type II zinc enolate aldolase is represented by E. coli fructose diphosphate (FDP) aldolase (bottom).

However, (26) should bind strongly to class II aldolases on account of its chelating ability and this has been found to be the case with rabbit muscle fructose diphosphate aldolase where (26) functions as a competitive inhibitor. Triose phosphate isomerase is also strongly inhibited by (26) this may be due to its similarity to the cw-eriediolate (28), which is an intermediate in the reaction pathway of this enzyme. Acyldihydroxyacetone phosphates are important intermediates in the biosynthesis of glycerolipids and the acyl... 

D-Fructose diphosphate aldolase (EC 4.1.2.13) catalyzes a reversible aldol reaction, yielding two different triose phosphates, as follows. 

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... 

Lebherz, H., and Rutter, W. (1969). Distribution of Fructose Diphosphate Aldolase Variants in Biological Systems, Biochemistry 8 109—121. 

Glutamate dehydrogenase and pyruvate dehydrogenase. Glucose 6-phosphatase NADPH-cytochrome reductase Fructose diphosphate aldolase Galactosyltransferase... 

Fig. 1-4A). Heterofermenters, however, lack the enzyme fructose-diphosphate aldolase and must divert the flow of carbon through the 6-phospho-gluconate pathway (pentose phosphate or phosphoketolase pathway) as depicted in Fig. l-4b to yield lactic acid as well as ethanol, acetic acid (depending on redox potential), and CO2. Energetically, the consequence of only half of the carbon returning to the EMP is formation of 1 mole of ATP/glucose.

DHAP (see Vol. 25, Chapter 7, Ref 44) with aldehydes 9, obtained by asymmetric dihydroxylation, gave after phosphatase treatment L-ftuctose (10), 6-C-plienyl-E>-g aibc/o-2-h ailose (11) or 7-deoxy-D-ga/oc/o-2-heptulose (12), Le., products with 3/ /4j/5j/(6/ )-stereochemistry, as shown in Scheme 3. The enantiomers of the three uloses were obtained by use of the hydroxylation auxiliaiy with the opposite chirality and fructose diphosphate aldolase as condensation catalyst. ... 

Sedoheptulose Diphosphate. The transaldolase reaction requires phos-phoglyceraldehyde, which has become available as a sjmthetic compound only recently. A convenient method for supplying those phosphate is to add fructose diphosphate and aldolase. When this device was used in a study of the transaldolase reaction, the reaction products of the system containing both aldolase and transaldolase, and hexose diphosphate and sedoheptulose phosphate were expected to include tetrose phosphate, as shown in equation (VI) above. Tetrose phosphate failed to accumulate, however. Instead, sedoheptulose-1,7-diphosphate was found to accumulate as a result of condensation of the tetrose ester with dihydroxy-acetone phosphate in the presence of aldolase. This diphosphate reacts rapidly with aldolase, and it is not known whether it can react in any other systems, or only shuttles back and forth in response to changes in tetrose phosphate level. 

Efficient utilization of the fructose requires phosphorylation of the glyceraldehyde. Tracer experiments show that the carbon 1 of fructose appears as both carbons 1 and 6 of glucose. This is the result of triose phosphate isomerization followed by (conventional) aldolase condensation to hexose diphosphate. The conversion of fructose diphosphate to glucose-6-phosphate requires a phosphatase and an isomerase, as discussed in the pentose phosphate pathway. 

The substrate here has a prochiral center and one hydrogen is transferred specifically only from one face (the re-face) of the double bond to the carbonyl function. It is primarily the chirality of the enzyme which determines the correct course of the reaction. Another example of this is when these same two substrates are in the presence of the enzyme aldolase, to give fructose diphosphate, the Hg rather than the Hg-hydrogen is exchanged with water. 

In 1934 dialyzed extracts of muscle and yeast were found to catalyze the cleavage of fructose diphosphate to dihydroxyacetone phosphate. A closer examination of this reaction revealed that instead of catalyzing the formation of dihydroxyacetone phosphate, the enzyme split fructose diphosphate to equal amounts of dihydroxyacetone phosphate and d-3-phosphoglyceraldehyde. This conclusion was based on the observations that (1) in the process of purifying aldolase, triosephosphate isomerase is removed and hence triosephosphates accumulate with no further change and (2) trapping agents, such as cyanide, hydrazine, and sulfite, will effec-... 

Its role in glycolysis is obvious, since it is responsible for the equilibration between the two triose units derived from the cleavage of fructose diphosphate by aldolase. The enzyme occurs in large amounts in skeletal muscle as well as in malignant tumors, brain, and yeast. Although Meyerhof and Beck have purified it some thirty times, this enzyme has not been extensively studied. The TN is enormous—some 1,000,000 per 10 g. protein. 

Glucose-6-P is then isomerized by phosphohexose isomerase to fructose-6-P (making up 30% of the equilibrium mixture). Another kinase phosphorylates the 1-position and the resulting fructose diphosphate is cleaved in an equilibrium reaction to two trioses, namely dihydroxyacetone phosphate (C-1 to C-3) and glyceral-dehyde phosphate (C-4 to C-6). The equilibrium mixture is composed of 89% hexose and 11% triose (under the conditions of Meyerhof s measurements) condensation, therefore, is the preferred (= exergonic) reaction. The reaction is analogous to the aldol condensation described in organic chemistry (Chapt. 1-2, XV-5). Catalysis of the reverse reaction by the enzyme aldolase is explained by the fact that enzymes always catalyze up to the equilibrium. ... 

Condensation of (5)-lactaldehyde with dihydroxyacetone phosphate in the presence of fructose diphosphate aldolase gave the 6-deoxyketose phosphate 12, and this, on treatment with acid phosphatase and then with sucrose synthase in the presence of UDPG, was converted into the 6-deoxy-L-sorbose disaccharide 13.1 ... 

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... 

Kelley, P.M. Freeling, M. (1984b). Anaerobic expression of maize fructose-1,6-diphosphate aldolase. Journal of Biological Chemistry, 259,14180-3. 

The hexose phosphate, fructose-1,6-diphosphate, is split by aldolase into two triose phosphates glyceraldehyde-3-phosphate and dihydroxyacetone phosphate. Aldolase consists of four 40-kDa subunits. Three tissue-specific forms exist in human tissues aldolase A (ubiquitous and very active in the muscle), aldolase B (liver, kidney, and small intestine), and aldolase C (specific to the brain). These three isozymes have nearly the same molecular size but differ in substrate specificity,... 

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. 

A syringolide 45, an elicitor of the bacterial plant pathogen Pseudomonas Siringae pv. tomato, has been synthesized in five steps via a fructose 1,6-diphosphate aldolase reaction (Scheme 95) <2000JOC4529>. 

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>... 

With zymohexase, fructose 1,6-diphosphate, and acetaldehyde, a 5-de-oxypentulose 1-phosphate resulted,66 and, with a pea-aldolase preparation, the product was identified as 5-deoxy-D-ilireo-pentulose (LXI). Using... 

---