Maltotetraose production

Similar instances, in which analytical data were of prime importance and where no products were isolated, are the oxidations of various di-D-fructose dianhydrides,80 inositols,81 the trisaccharide moiety of the alkaloid solamargine,82 2-O-a-L-fucopyranosyl-L-fucitol derived from fucoidin83 (a polysaccharide sulfate ester), trehalose and neotrehalose,84 maltotetraose,85 D-galactopyranosyl-glyceritol,86 and a 3-pentulose.87... 

Solutions of 1% (w/v) maltotriose, maltotetraose, maltopentaose, maltohexaose, and maltoheptaose were incubated at 60 C with purified enzyme (0.05 U/ml). Products were analyzed after 72 hours by HPTLC (Whatman HP-K). Plates were developed with n-BuOH EtOH H20 (3 3 2, v/v) at 25 C and the products detected with a mixture of 0.2% (w/v) orcinol in MeOH and 20% H2SO4 in MeOH (1 1, v/v). 

Maltotetraose was a very poor substrate for the enzyme and the products were observed only after long-term reaction. (Reprinted with permission from Ref. 13. Copyright 1990 Academic Press, Inc.)... 

Figure 3. Photograph of a paper chromatogram and a radioautogram of the products liberated from maltotetraose-l-14C by glucoamylase...

Hasegawa, K., Kubota, M., and Matsuura, Y. (1999). Role of catalytic residues in a-amylases as evidenced by the structures of the product-complexed mutants of a maltotetraose-forming amylase. Protein Eng., 12, 819-824. 

In these a-amylase reactions, glucose is not the primary product. Glucose is formed as a secondary product in the hydrolysis of maltotriose, maltotetraose and branched dextrins. Using 14C-reducing end labeled maltodextrins, G3 to G8, Robyt and French19 showed that porcine pancreatic a-amylase has different specificities for hydrolyzing the different linkages of the maltodextrins. The different frequencies for... 

Synthesis by P-enzyme occurs by multi-chain action, that is, all the acceptor substrate molecules are increased at approximately the same rate. With maltotetraose or maltohexaose as acceptor, the iodine-pro-duced stain of the products changes from red (degree of polymerization, DP,... 

A more careful examination of the products of action of pullulanase on pullulan showed the presence of a tetrasaccharide, in addition to maltotriose. In the sample examined, the tetrasaccharide was estimated to constitute 7% of the polysaccharide. The complete hydrolysis of this tetrasaccharide to maltose by sweet-potato befo-amylase, as well as optical rotation measurements, characterized it as maltotetraose. As earlier work had suggested that pullulan is a linear molecule, it was, therefore, of interest to ascertain how the maltotetraose units are arranged in the molecule. The two most likely possibilities are illustrated in Fig. 16b,c. 

Fig. 17.—Effect of Prior Treatment with aZpha-Amylase on the Products Liberated by Fullulanase from the Maltotetraose Residues in Pullulan.

The main degradation product (75-90%) resulting from the action of selected a-amylases on the a-D-glucan of Elsinoe leucospila has been identified as the trisaccharide O-a-D-glucopyranosyl-(l- 3)-0 -D-glucopyranosyl-(1 4)-D-glucose. This confirms previous reports that the polysaccharide consists chiefly of malto-triose units and a small proportion of maltotetraose units joined by (1 3)-a-D-... 

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