Maltotetraoses

Fig. 1 (A) Chromatographic separation of sugars. Track 1 fructose, 2 sucrose, 3 glucose, 4 mixture of the substances in tracks 1-3, 5 mixture of substances in tracks 1-3 and 6, 6 Fructo-oligosaccharides, 7 1-kestose, 8 mixture of glucose, maltose, maltotriose and maltotetraose. (B) Absorption scan of track 5 with 200 ng each substance per chromatogram zone 1 = fructosyl-nystose, 2 = nystose, 3 = 1-kestose, 4 = fructose, 5 = sucrose, 6 = glucose.

Fig. 10.—Circular Dichroism Spectra of Amylose (-), Maltohexaose (—), Maltotetraose...

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 2. Two maltotetraose models constructed from residues of glucose having different D. They have identical linkage bond and torsion angles.

Flypothetical interactions of a five-subsite enzyme with a maltotetraose substrate shown initially with a terminally radiolabeled (filled circles) nonreducing end. The vertical arrow indicates the glycosyl bond cleavage region the roman numerals indicate the subsites, and the 4 indicates the chain length. Only three binding interactions lead to hydrolysis IV,4 V,4 and Vl,4, and their different associated rate constants emphasize that the rates of hydrolysis need not be identical. From Allen and Thoma with permission of the Biochemical Society (London). 

Fig. 7 Maltotetraose hybrids with various carriers resulting in different chain architectures A poly(ethylene oxide) Ba and Bb poly(acrylic acid), amylose, cellulose, and other polysaccharides Ca cyclodextrin and multifunctional acids Cb amylopectin D crosslinked poly(acryl amide) [156] - Reproduced by permission of Wiley...

Pullulan is hydrolyzed by pullulanase at the a-(l - 6) bonds, producing maltotriose plus some maltotetraose. Salivary alpha amylase cleaves at the maltotetraosyl units, when the a-(1 -> 4) linkage next to the a-(1 -> 6) bond and towards the reducing end of the maltotetraose unit is split (dotted arrow marked A in 108). The size of units released by alpha amylase, as judged... 

Using the pure anomers of maltose in the same way, we found that crystalline hog pancreatic a-amylase causes the very rapid synthesis of maltotetraose from a-maltose but not from /3-maltose whereas, crystalline sweet potato /3-amylase causes the very rapid synthesis of the same compound, specifically from /3-maltose. Configurational inversion again marks this latter condensation as glycosyl-hydrogen interchange, or glycosyl transfer. 

Maltose and maltotriose were synthesized from a-glucosyl fluoride by all the a-amylases. Maltotetraose and sizeable amounts of the pentaose... 

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

The data in Table I show that the enzyme acts with highest velocity on maltotetraose and oligosaccharides of higher molecular weight. The rate of action on maltotriose is one-half of the rate for the tetrasaccharide, and on maltose the rate is only one-tenth of the rate for the tetrasaccharide. Oligosaccharides in which the glucose units are joined by linkages other than a-1,4 are hydrolyzed at much slower rates than the 1,4... 

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