Maltose maltotetraose from

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. 

We dived into Challenger Deep at the depth of 10,897m on March 2 1996 and have collected the mud samples. We have isolated strain MS300 which produces exo-maltotetraohydrase (amylase300) from the mud sample. The amylase300 predominantly maltotetraose from starch. This amylase300 to be very unique. Because, the exo-maltotetraohydrolase of Pseudomonas stutzeri strains had been reported but this enzyme produces glucose maltose and maltotriose besides maltotetraose from starch. We can expect the deep sea environment as the resource of novel microbial biocatalysts. 

A strain of Bacillus cereus synthesizes a pullulanase and a -amylase, which together convert starch into maltose in high yield. The homogeneous pullulanase was obtained by fractional precipitation, adsorption onto starch and Celite, and gel filtration. The purified enzyme (pH optimum 6.0—6.5, mol. wt. 1.10 0.20 X 10 ) released maltose, maltotriose, and maltotetraose from -limit dextrin and maltotriose from pullulan, but it did not release amylose-like substances from amylopectin. The enzymic activity was inhibited by mercuric chloride and 4-chloromercuribenzoate, although the activity in the latter instance could be restored by cysteine. 

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

Figure 9.72 Chromatograms of the action patterns of maltoheptaose after the indicated periods of incubation with a-amylase and a-glucosidase. Peaks 1, glucose 2, maltose 3, maltotriose 4, maltotetraose 5, maltopentaose (x) compound A 6, maltohexaose 7, maltoheptaose. (A) Pure maltoheptaose used for the assay. (B) Blank sample before the addition of substrate. (C-H) Chromatograms after 1, 5, 10,15, 20, and 30 minutes, respectively, of incubation. Chromatographic conditions column, 10 jum Nucleosil SA (250 mm X 4 mm) solvent, acetonitrile-water (72.527.5) flow rate, 0.7 mL/min temperature, 27°C detection, differential refractometer, full scale = 2 X 10-6 refractive index units. (From Haegel et aL, 1981.)...

The enzyme is readily prepared, in an apparently pure form, from the culture filtrates of this pseudomonad, and has a specific activity comparable to that of crystalline, sweet-potato befa-amylase. The exo action of the enzyme is analogous to that of heta-amylase, but maltotetraose residues, not maltose residues, are removed. The action of the enzyme is halted by branch points, so that limit dextrins are produced from glycogen and amylopectin. The specificity of the enzyme for linkages in the region of branch points has not yet been ascertained. Some applications of this enzyme will be discussed later (see p. 318). 

Plots of the CD intensity of 23 (1.00 x 10" M) at 405 nm versus [Mj. The solid lines represent the theoretical curves for the formation of the [23-(M )2] complex. Mj glucose, Mj maltose, M3 maltotriose, M4 maltotetraose, M5 maltopentaose. Reproduced with permission from ref. 27. 2000 John Wiley Sons. 

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