Monosaccharide production

Xg/mL Figure 8a) resulted in profiles containing a major A280 carbohydrate-containing peak of K3V = 0.56, cmc = 100 - 120 /xg/mL. In no instance was there evidence for enzyme catalyzed monosaccharide production. 

The enzymic digestion of an adenosine diphosphate sugar fraction from larch wood leads, among other monosaccharide products, to a fructose.20 This result suggests the occurrence of a corresponding fructosyl ester, but its structure remains undetermined. 

FIGURE 14.8 Electropherogram of an a-glucosidase II single-cell (Cell 7) reaction aliquot taken after incubation (a). Percent conversion of the dissaccharide (DG-TMR) substrate by a-glucosidase II in single cells and control assays (b). Percent conversion was calculated by comparing the DG-TMR peak to that of the monosaccharide product MG-TMR. (From Shoemaker, GK. et al.. Anal. Cheni., 77, 3132, 2005. With permission.)... 

FIGURE 18.15 In the Induced-fit model, a flexible active site and substrate both adjust to provide the best fit for the reaction. Sucrose binds to the active site to align the glycosidic bond for hydrolysis. The monosaccharide products are released, and the enzyme binds to another sucrose. 

Peonin, a red pigment found in the red peony, has the following structure. What are the monosaccharide products of the... 

Among the various types of sugars marketed, the mass consumption of sucrose far outweighs by volume the consumption of other products. Sucrose, also called table sugar, is a disaccharide which, upon hydrolysis, yields two monosaccharides glucose and fmctose. Various types of sugar vary in sweetness (1). 

Sucralose is quite stable to heat over a wide range of pH. However, the pure white dry powder, when stored at high temperature, can discolor owing to release of small quantities of HCl. This can be remedied by blending it with maltodextrin (93) and other diluents. The commercial product can be a powder or a 25% concentrate in water, buffered at pH 4.4. The latter solution may be stored for up to one year at 40°C. At lower pH, there is minimal decomposition. For example, in a pH 3.0 cola carbonated soft drink stored at 40°C, there is less than 10% decomposition after six months. The degradation products are reported to be the respective chlorinated monosaccharides, 4-chloro-4-deoxy-galactose (13) and l,6-dichloro-l,6-dideoxy-fmctose (14) (94). 

Recently, various monosaccharides have been employed as a source of 1,4-dicarbonyl compounds for pyridazine syntheses 70CB1846, 74CPB1732, 75JHC957). Moreover, diacylcyc-lopropanes have been also reported to give pyridazines the bicyclic products are transformed by P4S10 into the corresponding 3-thioxopyridazines 80JHC541). 

Thomson I Click Organic Interactive to predict products from reactions of simple monosaccharides. 

We saw in Section 25.6 that reaction of a monosaccharide with an alcohol yields a glycoside in which the anomeric -OH group is replaced by an -OR substituent. If the alcohol is itself a sugar, the glycosidic product is a disaccharide. 

Galactose, one of the eight essential monosaccharides (Section 25.7), is biosynthesized from UDP-glucose by galactose 4-epimerase, where UDP = uridylyl diphosphate (a ribonucleotide diphosphate Section 28.1). The enzyme requires NAD+ for activity (Section 17.7), but it is not a stoichiometric reactant. and NADH is not a final reaction product. Propose a mechanism. 

The cyclic product of condensation of two monosaccharide molecules with the elimination of two molecules of water (commonly called an intermolecular anhydride), is named by placing the word dianhydride after the names of the two parent monosaccharides. When the two parent monosaccharides are different, the one preferred according to the order of preference given in 2-Carb-2.1 is cited first. The position of each anhydride link is indicated by a pair of locants showing the positions of the two hydroxy groups involved the locants relating to one monosaccharide (in a mixed dianhydride, the second monosaccharide named) are primed. Both pairs of locants immediately precede the word dianhydride . 

De Bruijn et al.26 30 used chromatographic and spectroscopic techniques to analyze the effect of reaction variables (such as pH and monosaccharide concentration) on the product profile and developed a reaction model (see Fig. 9) that emphasized the role of a-dicarbonyl compounds. Some of the features of the model shown in Fig. 9 are ... 

Pyran derivatives, useful intermediates in the total synthesis of many monosaccharides and other natural products, have been synthesized by hetero-Dish-Alder reaction by using carbonyl compounds as dienophiles [9, 23]. 

Disaccharides are condensation products of two monosaccharide units. Examples are maltose and sucrose. 

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