Maltos-10 - Maltose

Hehre and coworkers showed that beta amylase from sweet potatoes, an inverting, a-specific exo-(l 4)-glucanase, catalyzes the hydrolysis of jS-maltosyl fluoride with complex kinetics which indicated the participation of two substrate molecules in the release of fluoride ion. Furthermore, the reaction was strongly accelerated by the addition of methyl ) -maltoside. Hydrolysis of a-maltosyl fluoride, on the other hand, obeyed Michaelis-Menten kinetics. The main product with both a- and yj-maltosyl fluoride was )S-maltose. The results with )3-maltosyl fluoride were interpreted by the assumption of a glycosylation reaction preceding hydrolysis by which a malto-tetraoside is formed by the replacement of fluoride ion by a second substrate molecule or added methyl -maltoside (see Scheme 5). 

The living character of the ROMP promoted by the initiator Ru(CHPh)(Cl)2 (PCy3)2 (Cy = cyclohexane) was tested with the synthesis of diblock, triblock, and tetrablock copolymers of norbornene derivatives carrying acetyl-protected glucose, [2,3,4,6-tetra-O-acetyl-glucos-l-O-yl 5-norbornene-2-carboxylate], A or maltose groups, [2,3,6,2/,3/,4/,6/-hepta-0-acetyl-maltos-1-O-yl 5-norbornene-2-carboxylate], B, shown in Scheme 41 [102]. The AB, ABA, and ABAB structures were prepared by sequential addition of monomers with narrow molecular weight distributions to quantitative conversions. 

B-chains until they are acted on by R-enzyme, when maltose or malto-triose will be produced from the residual A-chain, and linear dextrins from the B-chains. The amount of maltose or maltotriose liberated on treating the /3-limit dextrin with R-enzyme will be a measure of the number of A-chains in the molecule, and from these data, the ratio of A B chains in the molecule can be calculated.220 Peat concluded that multiple branching is an intrinsic part of the amylopectin structure, as the observed yield of these sugars was greater than expected for a singly-branched structure. It should be noted that glycogen has been shown by similar enzymic methods to possess a truly random structure.221... 

The thermodynamics of the maltose-binding protein of E. coli (MalE) have been studied using both DSC and ITC.117 This protein is a periplasmic component of the transport system for malto-oligosaccharides and is used widely as a carrier... 

Duan, X.Q., Hall, J.A., Nikaido, H., Quiocho, F.A. (2001). Crystal structures of the malto-dextrin/maltose-binding protein complexed with reduced oligosaccharides flexibility of tertiary structure and ligand binding. Journal of Molecular Biology, 306, 1115-1126. 

Table I (104) shows the yields of products from maltose to malto-pentaose recovered from digests of 0.2 M crystalline a-D-glucosyl fluoride with crystalline a-amylase preparations from six different biological sources. The digests were incubated at 30 °C for 10 minutes, heat inactivated, and chromatographed for product isolation and analysis.

The relative efficiencies of the malto-oligosaccharides, maltose to maltooc-taose, as acceptors were determined for Leuc. mesenteroides B-512FM dextransu-... 

Oxidation of lactose and maltose with Au/Ti02 catalysts has been reported to give close to 100% selectivity to lactobionic acid and malto-bionic acid, respectively63 which have potential uses in the pharmaceutical and detergent industries, as well as in food. Studies of the catalytic conversion of glucose by hydrogenation and oxidation to produce sorbitol and gluconic acid respectively have also been reported.64 Sorbitol is also manufactured on a 60 000 tonnes per annum scale. 

It appears that subsites of beta-amylase accommodate up to 6 D-glucosyl residues in a chain, with the point of hydrolysis being 2 D-glucosyl units from the nonreducing end. Maltohexaose and larger chains are split more rapidly than smaller molecules. Maltose and malto-tetraose lower the rate of action of the enzyme on molecules of larger size.11... 

TimCj min. Color with iodine Hydrolysis, % D-Glucose, % Maltose -h malto-Iriose, % a-Dextrins ... 

Advantose 100 Finetose-, Finetose F 4-O-a-D-glucopyranosyl-P-D-glucose 4-(a-D-glucosido)-D-glucose malt sugar malto-biose Maltodiose-, Maltose HH Maltose HHH Sunmalt Sunmalt S. 

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