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Amylase optical rotation

Total hydrolysis of the polymers gave D-glucose only. Water-soluble derivatives (ethyl or carboxymethyl ethers) of the polymers were unaffected by a-amylase, but were partially hydrolyzed by a ceUulase preparation from Acdobader xylinum. The optical rotations of several preparations of this polyglucose and of cellulose (P 1150) in tetraethylammonium hydroxide were all 0°, thereby strongly suggesting that the polyglucoses are /S-D-linked.109... [Pg.455]

Kooiman separated exocellular amylose formed in liquid media at pH < 5 by Cryptococcus albidus and Cryptococcus laurentii var. flavescens NRRL Y-1401 from a polysaccharide containing D-man-nose, D-xylose, and D-glucuronic acid. X-Ray diffraction patterns of the retrograded amyloses were identical with that of tuber starch (B modification). Periodate oxidation, optical rotational measurements, and hypoiodite oxidation data suggested a linear a-D-(l—>4)-linked structure having a chain length of about 44 units for the Cr. albidus amylose. Cryptococcus neoformans produces a crystalline amylose that was isolated by the method of Schoch. It has an iodine value and alpha- and hefa-amylase hydrolysis characteristics similar to those of corn amylose. [Pg.369]

The course of the optical rotation during the action of the malt a-amylase shows that the enzyme, as pointed out by Ohlsson, liberates the hydrolysis products in the a-configuration. A simple calculation shows that this is the case not only with the fermentable sugar but with the dextrins as well. [Pg.273]

A method capable of adaptation to B. macerans amylase assay is based upon the optical rotational shifts observed during coupling reactions (see p. 22f) and Fig. 21). ... [Pg.223]

A mixture of 0.25 g. of a-dextrin and 0.05 g. of u-glucose is treated with B. macerans amylase in a total volume of 25 ml. The optical rotation is measured from time to... [Pg.223]

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. [Pg.334]

Table VI summarizes the properties of the native, partially sulfated, and 3,6-anhydro- derivative of elsinan. The 3,6-anhydro-elsinan contained 3,6-anhydro-glucose residues, approximately a half of the original (1 4)-linked glucose residues. The anhydro-elsinan showed a low optical rotation. In i.r. spectrum the formation of a new absorption band at 895 cm" was recognized. These results suggest the changes in the conformation of a-(1 4)-linked glucose residues from C-1 to 1-C forms. The introduction of 3,6-anhydroring to elsinan gives very low viscosity, and also the resistance to the action of salivary amylase. Table VI summarizes the properties of the native, partially sulfated, and 3,6-anhydro- derivative of elsinan. The 3,6-anhydro-elsinan contained 3,6-anhydro-glucose residues, approximately a half of the original (1 4)-linked glucose residues. The anhydro-elsinan showed a low optical rotation. In i.r. spectrum the formation of a new absorption band at 895 cm" was recognized. These results suggest the changes in the conformation of a-(1 4)-linked glucose residues from C-1 to 1-C forms. The introduction of 3,6-anhydroring to elsinan gives very low viscosity, and also the resistance to the action of salivary amylase.
Endo-amylase (a-amylase) has a liquefying effect, since the viscosity of a colloidal starch solution decreases rapidly and the iodine color reaction disappears without the appearance of reducing sugars. The reducing effect develops later, in a second phase, when the fragments have been broken down further. Maltose is released in the a-form (the optical rotation drops, however, due to muta-rotation) hence the name of the enzyme. [Pg.307]


See other pages where Amylase optical rotation is mentioned: [Pg.338]    [Pg.277]    [Pg.264]    [Pg.513]    [Pg.527]    [Pg.232]    [Pg.246]    [Pg.260]    [Pg.10]    [Pg.450]    [Pg.477]    [Pg.503]    [Pg.419]    [Pg.245]    [Pg.299]    [Pg.213]   
See also in sourсe #XX -- [ Pg.486 ]




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