Maltose oligomers

The torsion angles of glycosidic bonds of maltose oligomers and cyclohexaamylose, and their O-acetyl derivatives, have been deter-... 

Lankamycin Leukomycin Lincomycin HC1 Megalomycin A and C2 Maltose oligomers... 

Fig. 3-113. Separation of maltose oligomers. - Separator column CarboPac PA-1 eluent (A) 0.1 mol/L NaOH, (B) 0.1 mol/L NaOH + 1 mol/L NaOAc gradient 100% A for 2 min isocratically, then linearly to 100% B in 200 min flow rate 1 mL/min detection and injection volume see Fig. 3-105 solute concentrations 166 ppm each of maltose (1), maltotriose (2), maltotetraose (3), maltopentaose (4), maltohexaose (5), and maltoheptaose (6).

Hydrophilic interaction liquid chromatography in gradient mode with charged aerosol detection can also be used for separating oligosaccharides. As an example, Figure 8.83 shows the separation of maltose oligomers up to DP7 on... 

Fig. 3-180. Separation of maltose oligomers. - Separator column CarboPac PAl eluant ...

The maltose-based oligomers are exact linear analogues of CDs. For example, maltoheptaose is composed of seven a(l-4)-linked glucose units such as p-CD. Its linear chain is sufficiently flexible to wrap around guest molecules and form quasi-inclusion complexes in the gas phase." " ... 

Cellulose, starch, and their derivatives are commonly used as chromatographic stationary phases. They are, in principle, potential hosts for inducing CD activity in small molecules and could be used with effect for analysis in homogeneous media with chiroptical detection. An example might be the starch (amylose)-iodide complex [86]. Low aqueous solubility however is an obstacle to their general use in homogeneous solutions. Linear oligomers of maltose are more soluble than starch and could theoretically be used as alternatives to Cy, however they do not really compete in terms of the stability of the association complexes. 

Another common method for determination of alpha-samylase involves measurement of the diminution of the iodine-stainability of whole starch or amylopectin )8-limit dextrin. These methods are useful, as very small quantities of alpha-amylase may be estimated in this way. They are comparative, and cannot be used to determine rates of bond scission, unless they are carefully calibrated by a method that measures reducing end-groups. Such a calibration has been made for the action of hog-pancreas alpha-amylase on waxy-maize starch, although the validity of the reducing-power determinations, made with iodine and thiosulfate, has been confirmed for maltose only thus, it is not yet known whether the calibration is actually valid for the experimental system in which larger oligomers, for example, the triose and tetraose, are also formed. 

Saliva and pancreatic juice both contain a-amylase. The activity of this enzyme in saliva is not significant compared with that in the pancreatic juice released into the gut. Release of amylase from the pancreas is controlled by a mechanism similar or identical to the one that stimulates the release of tr)rpsinogen, namely by the influence of CCK on the exocrine pancreas. Amylase catalyzes the hydrolysis of starch at interior positions rather than at the ends of the polymer. This activity yields products such as maltose and longer-chain-length oligomers of glucose. Also, amylase does not catalyze the hydrolysis of starches at branching points. Therefore, small branched-chain structures called dextrins are formed that are not hydrolyzed by the er zyme. 

Coarse grain MSB model (black) and atomistic model (gray) of the simplest a(l — 4) glucose oligomer, the dimer ct-maltose. The coarse grain particles Bl, B4 and B6 representing each monomer are mapped from the positions of the carbons Cl, C4, and C6 of the atomistic model, respectively. 

Lourdin, D., Ring, S.G., and Colonna, P. Study of plasticizer-oligomer and plasticizer-polymer interactions by dielectric analysis maltose-glycerol and amylose-glycerol-water systems, Carbohydr. Res., 306, 551, 1998. 

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