Di hydroxy acetone

Figure 2. Free energy profile for converting di hydroxy acetone phosphate, the substrate (abbreviated S) and glyceraldehyde 3-phosphate, the product (abbreviated P), with intermediate formation of the enedi-olate (abbreviated Z). Catalysis occurs either by a free carboxyl group (levels connected by dotted lines) or by triose-phosphate isomerase (levels connected by dashed lines). The vertical arrows show the limits of those states that are less well defined as a result of uncertainty in the experimental data. The transition state marked "e" refers to the exchange of protons between the solvent and the enzyme-bound enediol intermediate (EZ). Reproduced with permission of the authors and the American Chemical Society.

Fructose 1,6-bisphosphate is cleaved to glyceraldehyde 3-phosphate and di hydroxy acetone phosphate. 

From Glycerose.—A second synthesis of hexoses is the aldol condensation of glycerose, as already referred to (p. 337). As glycerose is a mixture of the two compounds, glyceric aldehyde (aldo triase), and di-hydroxy acetone keto-triose) the condensation product is the keto-hexosej or fructose. 

Monosaccharides, the simplest carbohydrates, are aldehydes or ketones that have two or more hydroxy] groups the empirical formula of many is (CJ—literally a carbon hydrate. Monosaccharides are important fuel molecules as well as building blocks for nucleic acids. The smallest monosaccharides, for which n = 3. are di hydroxy acetone and D- and L-glyceraldehvde... 

Di hydroxy acetone is the simplest ketose. The stereochemical relations between D-ketoses containing as many as six carbon atoms are shown in Figure 11.3. Note that ketoses have one fewer asymmetric center than do aldoses with the same number of carbons. D-Fructose is the most abundant ketohexose. 

Butlerov found out that in alkaline medium (calcium hydroxide), formaldehyde HCHO polymerizes to form about 20 different sugars as racemic mixtures, Butlerov 1861. The reaction requires a divalent metal ion. Breslow found a detailed mechanism of reaction that explains the reaction products, (Breslow 1959). He found that glycol-aldehyde is the first product that is subsequently converted into glyceral-dehyde (a triose), di-hydroxy-acetone, and then into various other sugars, tetrose, pentose, and hexose. The formose reaction advances in an autocatalytic way in which the reaction product is itself the catalyst for that reaction with a long induction period. The intermediary steps proceed via aldol and retro-aldol condensations and, in addition, keto-enol tautomerizations. It remains unexplained how the phosphorylation of 3-glyceraldehyde leads to glycral-3-phosphate (Fig. 3.6). Future work should study whether or not ribozymes exist that can carry out this reaction in a stereo-specific way. 

The structural unit of the phosphoglycerides is D-glycerol-3-phosphate, a derivative of the trivalent alcohol glycerol. The compounds glycerol and di-hydroxy-acetone were detectable in the Murchison meteorite. This does seem noteworthy as these biogenic compounds are not in the products of the prebiotic soup. What is the mechanism of lipid formation in meteorites This question has not been answered. 

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