Amylose phosphate, preparation

Amylose triacetate prepared from butanol-precipitated starch may be plasticized with almost any of the common plasticizers which are applicable to the plasticization of cellulose triacetate. For example, some suitable plasticizers are dimethyl or diethyl tartrate, tributyl citrate, tributyl phosphate, tricresyl phosphate, polyethylene glycol, and pentaerythritol tetraacetate. Addition of only 10-20% plasticizer is sufficient to give amylose triacetate films a useful and lasting degree of... 

Maltooligosaccharides (artificial amyloses) were prepared by polycondensation of a-D-maltosyl fluoride using a-amylase as the catalyst in a mixed solvent of methanol—phosphate buffer (pH 7).130 The yielded maltooligosaccharides contained a mixture from tri-ose to heptaose. The formation of the odd-numbered maltooligosaccharides may be due to enzymatic hydrolysis of the products during the reaction. The... 

The fact that glycogen phosphorylase can be used to polymerize amylose was first demonstrated by Schaffner and Specht [110] in 1938 using yeast phosphorylase. Shortly after, the same behavior was also observed for other phosphorylases from yeast by Kiessling [111, 112], muscles by Cori et al. [113], pea seeds [114] and potatoes by Hanes [115], and preparations from liver by Ostern and Holmes [116], Cori et al. [117] and Ostern et al. [118]. These results opened up the field of enzymatic polymerizations of amylose using glucose-1-phosphate as monomer, and can be considered the first experiments ever to synthesize biological macromolecules in vitro. 

Amaranth starch has very small and very uniform granules, the majority being less than 1 micrometer in diameter. Starch isolated from two Amaranthus species was compared and found to contain approximately 90% amylopectin and 10% amylose.164 Those authors prepared distarch phosphates and found that A. hypochondriacus starch responded more to crosslinking, as evidenced by reduced swelling power at 85°C and an increased gelatinization temperature range than did A. cruentus starch. 

Amylose was also prepared via in vitro polymerization of D-glucosyl phosphate catalyzed by a potato phosphorylase (120). A large excess amount of Glc-l-P is required in this equilibrium-controlled reaction. 

It is the amylose component of starch that gives the blue color when KI/I2 solution is added. To study the iodine-iodide color of amyloses of different d.p. values, maltodextrin-amylose molecules, with various avg. d.p. values from 6 to 568 were prepared by Bailey and Whelan [62], using phosphorylase, a-D-glucopyranosyl-1-phosphate, and maltohexaose. The colors of the various sized maltodextrins (1 mg) were observed when 10 1 (w/w) KI/I2 solution was added. The first color to be observed was faint red for avg. d.p. 12 a red-purple color was observed for avg. d.p. 31 a purple color was observed for avg. d.p. 40 and a blue color was observed for avg. d.p. 45. The increase in the blue value was linear as a function of avg. d.p. up to avg. d.p. 60 the absorbance at 645 nm then slowly increased and reached a maximum at avg. d.p. of 400. The intensity of the iodine/iodide color in the low molecular weight range was dependent on the concentration of the iodine. When the concentration of the iodine was increased 10-fold, the intensity was increased 50% [62]. 

Muscle phosphorylase synthesizes an amylose from a-n-glucopyranosyl phosphate, whilst impure heart and liver preparations give polysaccharides with the physicochemical properties of a glycogen (ref. 27). 

Gilbert and Watkins have used highly purified and crystalline preparations for such synthetic work. By these means, amyloses of a DP of 10 have been prepared. There is, therefore, good evidence for the view that P-enzyme can synthesize, from a-D-glucosyl phosphate, amylose-type molecules which approach the size of natural amylose. 

Numerous analogs of carbohydrate polymers (i.e., amylose, glycogen) have been prepared from modified monosaccharide 1-phosphates with phosphorylase (Fig. 13-11 shows the natural substrates) l159 162l. 

Synthetic amyloses have been prepared from maltopentaose and D-glucose 1-phosphate by the action of potato phosphorylase. The products were characterized by the analysis of the products of /3-amylolysis and were used as standards in the determination of the molecular weight of starches by gel chromatography. 

The vine-twining polymerization is a method for the preparation of well defined supramolecules, which are amylose pol5mer inclusion complexes (70). The method consists of the enz5matic pol5meriza-tion of a-D-glucose-l-phosphate catalyzed by phosphorylase in the presence of various S mthetic pol mers such as polyethers, polyesters, poly(ester ether)s, and amphiphilic block copol5mers. The IH-NMR spectra of the polymers indicated structures composed from amylose and guest pol mers. 

Styryl amylose amide (VAA) was prepared from maltopentose-substituted styrene (VM5A) by phosphorylase-catalyzed pol3unerization of glucose-1-phosphate (Glu-lP) (118) (Fig. 8). Subsequent radical copolymerization with acrylamide gave the corresponding graft copolymers.. 

A Naegeli-type amylodextrin of DP 21 and containing one branch-point in each molecule has been prepared from waxy corn starch. The adsorption of monobasic fatty acids from n-hexane on to dry amylose has been found to follow Langmuir s adsorption isotherm. Changes in the physical properties of a potato starch with a high content of phosphate in the presence of cations have been described. Alkali-metal cations produced an increase in the viscosity of solutions of this potato starch, whereas alkaline-earth-metal cations initiated a two-step swelling process and lowered the viscosity. 

The specific activities of purified preparations of human parotid and pancreatic amylases towards Amylose Azure, Remazol Brilliant Blue starch, phosphate-derivatized starch, and cross-linked starch have been measured. The activities varied with the physical state of the substrate the parotid enzyme exhibited a higher specific activity towards all soluble starches, whereas the pancreatic amylase was more active towards insoluble chromogenic starches. Variations in the enzyme-substrate interactions support the view that there is a configurational difference between the amylases this may be useful in determining the proportions of these amylases in normal and pathological body fluids. 

Landerito NA, Wang Y-J. 2005. Preparation and properties of starch phosphates using wrixy, common, and high-amylose corn starches. II. Reactive extmsion method. Cereal Chem 82 271-276. 

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