Disaccharide Cellobiose Lactose Maltose

C. beijerinckii (formerly C. acetohutylicum) NCIMB 8052 prefers glucose as substrate but also ferments glucitol, galactose, and the disaccharides cellobiose, lactose, maltose, and sucrose [25]. C. beijerinckii NCIMB 8052 is a grampositive, rod-shaped, obligately anaerobic, mesophylic bacterium and possesses peritrichous flagella. 

Two sugars can link to each other by losing water from OHs to form disaccharides. Figure 4.6 shows the Haworth projection formulas of four important disaccharides sucrose, lactose, maltose, and cellobiose, which all have the same molecular formulas, C12H22011. Sucrose and lactose are the most abundant and most important disaccharides of natural origin. Maltose and cellobiose are repeating units of polymeric starch and cellulose, respectively. Disaccharides may hydrolyze to form two monosaccharide molecules. 

Directing effects of substituents. See Electrophilic aromatic substitution Disaccharide, 973, 991-993, 1008. See also Cellobiose Lactose Maltose Sucrose Disparlure, 239... 

Lactose is a disaccharide constituting 2-6% of milk and is known as milk sugar. It differs from maltose and cellobiose in that only one of its monosaccharide units is D-glucose. The other monosaccharide unit, the one that contributes its anomeric carbon to the glycoside bond, is D-galactose. Like cellobiose, lactose is a p-glycoside. 

Disaccharides cellobiose and cellobiulose, (gentiobiose, isomaltose, kojibiose, laminarabiose, leucrose, melibiose, nigerose, palatinose, sophorose, trehalose, turanose, and xylobiose), lactose and lactulose, maltose and maltulose ... 

In 1896, Fischer developed the phenylhydrazine test" for the detection of hydrolytic scission of disaccharides, especially by enzymes this depends on the fact that the phenylosazones of disaccharides are soluble in hot water, whereas those of the monosaccharides are not. Lactose is hydrolyzed by emulsin (1894) and by lactase it is not fermentable by yeast, and is unaffected by invertase (1894). An extract of the small intestine of horses and cattle, especially from young animals, hydrolyzes lactose (1896). The action of enzymes on lactose allowed it to be classified, along with cellobiose and maltose, with the normal (and not the y-type of) methyl glucoside (1914). In the discussion of maltose, the relationship of lactose to the /9-series will be mentioned later. 

Four commonly occurring disaccharides. The configuration about the hemiacetal group has not been specified for lactose, maltose, or cellobiose because both anomers exist in equilibrium. 

Importantly, this halogenation process can be extended to members of the disaccharide series, and the lactose, maltose, and cellobiose derivatives 61, 62, and 63 afford the crystalline a-glycosyl bromides 64,65, and 66 in almost quantitative yields (see Scheme 10).51 As these O-benzoylated oximes are... 

Disaccharides are formed by the union of two monosaccharides with the loss of one molecule of water. Disaccharides include lactose, cellobiose, maltose, and sucrose. The molecular formula for sucrose is as follows ... 

It has long been known that D-glucose substituted at C4, as in the disaccharides lactose, cellobiose, and maltose (see page 48), is particularly suitable for the preparation of a -D-isosaccharinic acid through treatment with lime-water. Since this acid is only a minor product of the action of alkali on unsubstituted D-glucose, the presence of a substituent at C4 must preferentially direct the alkaline degradation to the isosaccharinic structure. 

Disaccharides are complex carbohydrates in which two simple sugars are linked by a glycoside bond between the anomeric carbon of one unit and a hydroxyl of the second unit. The two sugars can be the same, as in maltose and cellobiose, or different, as in lactose and sucrose. The gly-cosidic bond can be either a (maltose) or j3 (cellobiose, lactose) and can involve any hydroxyl of the second sugar. A 1,4 link is most common (cellobiose, maltose), but others such as 1,2 (sucrose) are also known. 

Glycosidic bonds between monosaccharides give rise to oligosaccharides and polysaccharides. The simplest oligosaccharides, the disaccharides, include compounds such as sucrose and lactose, which are referred to as sugars (like the monosaccharides). Other common disaccharides include trehalose, maltose, gentiobiose, and cellobiose. 

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