Polysaccharides enzymic degradation

Enzymes Degrading Macromolecules. Enzymes that degrade macromolecules such as membrane polysaccharides, stmctural and functional proteins, or nucleic acids, have all shown oncolytic activity. Treatment strategies include the treatment of inoperable tumors with pepsin (1) antitumor activity of carboxypeptidase (44) cytotoxicity of ribonudease (45—47) oncolytic activity of neuraminidase (48—52) therapy with neuraminidase of patients with acute myeloid leukemia (53) antitumor activity of proteases (54) and hyaluronidase treatment in the management of human soHd tumors (55). 

Finally, the A. aculeatus preparation was found to contain an enzyme releasing the dimer B-Xylp-(l-3)-GalAj, from a soluble soy cell wall polysaccharide. The enzyme was partially purified and appeared to be active towards saponified MHR and gum tragacanth as well. It was concluded that this enzyme degraded the xylogalacturonan part in MHR by an exo-fashion. 

Karl MyrbAck, Products of the Enzymic Degradation of Starch and Glycogen 252 M. Stacey and P. W. Kent, The Polysaccharides of Mycobacterium tuberculosis 311 R. U. Lemieux and M. L. Wolfrom, The Chemistry of Streptomycin. 337... 

The extracellular polysaccharides of Rhizobium meliloti 201 have been examined by using enzymic degradation and chemical procedures.314 A mixture of polysaccharides produced by the bacterium, when incubated with a bacterial enzyme that hydrolyzed one of these, gave oligosaccharides that could be separated by DEAE-cellulose chromatography. The major fraction was a pentasaccharide, for which methylation analysis and Smith... 

Y. Yoshizawa, J. Tsunehiro, K. Nomura, M. Itoh, F. Fukui, A. Ametani, and S. Kaminogawa, In vivo macrophage-stimulation activity of the enzyme-degraded water-soluble polysaccharide fraction from amarine alga (Gracilaria verrucosa), Biosci. Biotechnol., Biochem., 60 (1996) 1667-1671. 

As a result of the various acidic and enzymic degradative studies on chitin, there can be little doubt that the polysaccharide is a homogeneous polymer composed of 2-acetamido-2-deoxy-D-glucose residues. Moreover, the specificity of chitinases as 2-acetamido-2-deoxy-/3-D-glucosidases confirms the /3-d nature of the glycosidic linkages. 

In the following discussion, formulas for amylopectin and glycogen based on these calculations will be used as working hypotheses for the understanding of the enzymic degradation of the polysaccharides. 

Enzymic degradation experiments on the polysaccharide were unsuccessful, Hydrolysis was carried out with 2.5% sulfuric acid, and in the hydrolyzate, D-mannose was identified as the phenylhydrazone, D-arabin-ose as the benzylphenylhydrazone and D-galactose as the methylphenyl-hydrazone.,. The acidic components gave a negative naphthoresorcinol test for hexbronic acids, though indications of the presence of glycolic acid were claimed. 

Plug degradation could also be achieved by enzymes being directly incorporated into the plug. In an example, plugs containing pectin, a natural polysaccharide, were degraded by pectinolytic enzymes, whereby the lag time of the system was controlled by the ratio of pectin to enzymes (Fig. 10). 

Alpha-glucosidase inhibitors are competitive inhibitors of la-glucosidases, enzymes that are located in the brush border of epithelial cells, mainly in the upper half of the small intestine. The enzymes degrade complex carbohydrates into monosaccharides, which are absorbed. The alpha-glucosidase inhibitors bind reversibly in a dose-dependent manner to the oligosaccharide binding site of these enzymes and delay the degradation of polysaccharides and starch to... 

An additional problem in limit-dextrin analysis requires comment. Assuming (a) complete phosphorolysis and /3-amylolysis and (b) the presence of equal numbers of A- and B-chains, the difference A between the CL of a d>-dextrin and a S-dextrin of various polysaccharides should be constant. This is not the case. With rabbit-liver glycogen, wheat amylopectin, and maize amylopectin, A was 1.8, 2.6, and 2.7 n-glucose residues, and for seventeen other polysaccharides, A varied between 1.1 and 2.6. If the ( -dextrin had single-unit A-chains, this variation could be ascribed to differences in the ratio of A-chains to B-chains. This conclusion is probably incorrect, and no ready explanation for the variation in A is available as, in all the experiments, enzymic degradation was essentially complete. 

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