Of maltose

Diastase or amylase is formed when malt is produced by the germination of barley grains. Malt is therefore a good source of the enzyme. Diastase is also secreted by the salivary glands (when it is known as ptyalin), and also by the pancreas. Its function is to hydrolysef starch to a mixture of maltose and dextrin ... 

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... 

The two stereoisomeric forms of maltose just mentioned indergo mutarotation when dissolved in water What is the structure of the key intermediate in this process ... 

Amylase occurs in many plants, such as barley, wheat, rye, soy beans, and potatoes, where it is generally accompanied by some a-amylase. [ -Amylase initiates hydrolysis at the nonreducing end of an amylose or amylopectin chain, and removes maltose units successively until the reducing end of the molecule is encountered in amylose or a branch is met in amylopectin. ( -Amylase is used commercially in the preparation of maltose symps. After P-amylase hydrolysis of amylopectin there remains a P-amylase limit dextrin. ( -Amylase has been used as a probe of the fine stmcture of amylopectin (43-46). 

Important physical and functional properties of maltose and maltose symps include sweetness, viscosity, color stabiUty, humectancy, freezing point depression, and promotion of beneficial human intestinal microflora growth. Maltose possesses ca 30—40% of the sweetness of sucrose in the pure state (32). 

Maltitol (4-0-a-D-glucopyranosyl-D-glucitol) formed by catalytic hydrogenation of maltose (97), has been obtained both as a noncrystalline powder and a viscous Hquid (98). Stmctures of disacchatide alcohols are shown ia Figure 3. 

Fermentabihty of com symps by yeast is important in certain food appHcations, eg, baking and brewing. The fermentable sugars present in corn symp are dextrose, maltose, and maltotriose. Fermentabihty of maltose or maltotriose depends on the specific fermentation process and organism. In general, greater fermentabihty is obtained at higher DE levels. 

Amylases are exoen2ymes that attack amylose chains and result in the successive removal of maltose units from the nonreducing end. In the case of amylopectin, the cleaving stops two to three glucose units from the a-1,6-branching points. ( -Amylase [9000-91-3] is used for the production of maltose symps and for adjunct processing in breweries. The most important commercial products are made from barley or soybeans. 

By taking advantage of the remarkable abihty of subtihsia [9014-01-1] to remain catalyticahy active ia anhydrous dimethylformamide, a number of carbohydrates and other sugar-related compounds have been regioselectively acylated with trichloroethyl butyrate (100). In the case of maltose [69-79-4] (76) and sahcia [138-52-3] (77), for example, acylation occurs exclusively at the C-6 positions. 

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

Rate of permeation relative to tliat of maltose. Data adjusted to 100 s for maltose. The LamB-containing liposomes were added to buffer solutions containing 40 mM of die corresponding test sugars. 

Many enzymes are extremely specific. For example, the enzyme maltase catalyzes the hydrolysis of maltose ... 

Write a chemical equation, using molecular formulas, for the reaction of maltose with water to form glucose. 

Using bond energies, estimate AH for the hydrolysis of maltose to... 

The structure of maltose (far right). A glycosidic bond links different ring carbon atoms of two glucose molecules. ... 

Fadel, H.H. and Farouk A., Caramelization of maltose solution in presence of alanine, Amino Acids, 22, 199, 2002. 

A similar synthesis starting from the derivatives of maltose (55), lactose (46), and cellobiose (57) to give the L-asparagine derivatives 56,48, and 58, respectively, was accomplished by Dunstan and Hough.46... 

Levitt, M., C. Fine, J. Furne, and D. Levitt. Use of maltose hydrolysis measurements to characterize the interaction between the aqueous diffusion barrier and the epithelium in the rat jejunum., /. Clin. Invest. 1996, 97, 2308-2315... 

Fehr, M., Frommer, W. B. and Lalonde, S. (2002). Visualization of maltose uptake in living yeast cells by fluorescent nanosensors. Proc. Natl. Acad. Sci. USA 99, 9846-51. 

In41 the foregoing proof of the structure of turanose, the generally accepted structure of maltose which has come from the evidence supplied... 

Rm indicates in a general way the D-glucosyl component of maltose, and Rt that of turanose. One OH becomes O when a position of union is specified.)... 

One notices that the data from the oxidation of melezitose by per-iodic acid confirm the pyranose structure of the D-glucose unit in turanose, and therefore also in the case of maltose, in agreement with the original assignments for both of these disaccharides from methylation studies. 

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