Maltose and cellobiose

Maltose obtained by the hydrolysis of starch and cellobiose by the hydrolysis of cellulose are isomenc disaccharides In both maltose and cellobiose two d glucopyra nose units are joined by a glycosidic bond between C 1 of one unit and C 4 of the other The two are diastereomers differing only m the stereochemistry at the anomeric carbon of the glycoside bond maltose is an a glycoside cellobiose is a (3 glycoside... 

FIGURE 25 6 Molecu lar models of the disaccha rides maltose and cellobiose Two D glucopyranose units are connected by a glycoside linkage between C 1 and C 4 The glycosidic bond has the a orientation in maltose and IS p in cellobiose Mai tose and cellobiose are diastereomers... 

Both maltose and cellobiose have a free anomeric hydroxyl group that is not involved in a glycoside bond The configuration at the free anomeric center is variable and may be either a or (3 Indeed two stereoisomeric forms of maltose have been iso lated one has its anomeric hydroxyl group m an equatorial orientation the other has an axial anomeric hydroxyl... 

Lactose is a disacchande constituting 2-6% of milk and is known as milk sugar It differs from maltose and cellobiose m 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 (3 glycoside... 

Maltose and cellobiose (Section 25 14) are examples of disaccharides denved from D glucopyranosyl units... 

You can view molecular models of maltose and cellobiose on Learning By Modeling. 

Maltose and cellobiose are both reducing sugars because the anomeric carbons on the right-hand glucopyranose units have hemiacetal groups and are in equilibrium with aldehyde forms. For a similar reason, both maltose and cellobiose exhibit mutaiotation of a and /3 anomers of the glucopyranose unit on the right. 

Figure 4.19 The structures of the disaccharides maltose and cellobiose, derived from the hydrolysis of starch and cellulose, respectively.

Figure 9.15 Structure of disaccharides. Maltose and cellobiose are both disaccharides which contain only glucose units, the difference in their structures lying in the way the glucose units are joined. The glycosidic linkage in maltose is afl—>4), whereas that in cellobiose is (1—>4).

A short presentation of the Consistent Force Field is given, with emphasis on parametrization and optimization of energy function parameters. For best possible calculation of structure, potential energy functions with parameter values optimized on both structural and other properties must be used. Results from optimization with the Consistent Force Field on alkanes and ethers are applied to glucose, gentiobiose, maltose and cellobiose. Comparison is made with earlier and with parallel work. The meaning and use of conformational maps is discussed shortly. 

Disaccharides are molecules that break apcirt into two monosaccharides during hydrolysis. Examples include sucrose, maltose, and cellobiose. We cover all three of these disaccharides in the next sections. 

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... 

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. 

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