Cellulose cellotriose from

Degradation of oat and barley glucans with Streptomyces cellulase, which produces mainly cellobiose and cellotriose from cellulose, resulted in production of a trisaccharide fraction and a tetrasaccharide fraction as the major products. These were isolated by preparative paper-chromatography, and the trisaccharide was found to preponderate ... 

In respect to its ability for degrading H3P04-swollen cellulose, Ci is similar to Cx, but the mode of attack clearly is different (Figure 2). Whereas Ci attacks from the end of the chain and produces little change in degree of polymerization, Cx attacks at random. Glucose, cellobiose, and cellotriose are found in the products of the action of Cx C i produces principally cellobiose, as would be expected from a cellobiohydrolase. 

Figure 14. Paper chromatogram of the hydrolysis products from higher cellulose substrates by Ex-1. Developed by the descending technique for 96 hr at room temperature on Whatman No. 1 paper, using 1-butanol pyridine water (6 4 3, v/v) as a solvent (S) standard, (Gt) glucose, (Gz) cellobiose, (Gs) cellotriose, (Gu) cellotetraose, (G5) cellopentaose, (G6) cellohexaose final enzyme concentration 2.82 X 10 2%.

Endoglucanase and cellobiohydrolase enzyme fractions, obtained from DEAE-Sepharose column chromatography of crude enzyme from in-house-grown T. reesei culture filtrates, were examined for activity on cellulose. As expected, cellobiohydrolase action resulted in cellobiose formation while cellotriose as well as cellobiose was formed by the action of endoglucanase. In both cases, the formation of glucose was minimal. Examination of the combined activity of these components on celluloses, showed a certain degree of synergism does exist. 

Figure 7. Analysis of normal and reduced members of the cellulose oligosaccharide series by charcoal chromatography. Components from left to right Glucose (G1) reduced cellobiose (G2H borohydride reduction) cellobiose (G2) reduced cellotriose (G3H) cellotriose (G3) reduced cellotetraose (G4H) cellotetraose (G4), and reduced cellopentaose (G5H)...

Pseudomonas fluorescens produced two extracellular (A and B) and one cell-bound (C) cellulase components, the latter being released by treatment with EDTA-lysozyme in isotonic sucrose. Culture with 0.5% glucose formed little cellulase. Cellobiose stimulated only the synthesis of C. The formation of A and B was strikingly enhanced in cultures with cellulose, sophorose, or continuous low concentration of cellobiose. The absence of extracellular cellulase synthesis in 0.5% cellobiose culture may be caused by catabolite repression. The three cellulases were purified and characterized. None of them split cellobiose, but all hydrolyzed various cellodextrins and celluloses. C easily attacked cellotriose and cellotriosyl sorbitol, but A and B had no effect. When pure B was incubated with broken spheroplasts of sophorose-grown cells, a cellulase component indistinguishable from A was formed. 

These enzymes differ from other exo-hydrolases by not hydrolyzing their substrates at unique sites, at least with the / -l,4-oligoglucosides of CL up to 6. When swollen cellulose was the substrate, cellobiose was an important product for each of the enzyme fractions, but there is no information as to whether cellotriose was also a product. The polarity of attack and the inversion of the configuration of the oligosaccharides released, distinguish this enzyme from endo-hydrolases. 

The n.m.r. spectra of peracetylated cello-oligosaccharides have been recorded and compared with that of cellulose acetate.All of the signals from cellulose acetate were only observed in the spectra of cellotetraose and cello-pentaose peracetates. Some signals were not observed in the spectra of cellobiose and cellotriose peracetates. 

Cellulose is a carbohydrate, the structure of which may be deduced as follows. The molecular formula of cellulose is (C6HioOs)n, where n is a few thousand (see later). Hydrolysis of cellulose by boiling with concentrated hydrochloric acid yields D-glucose (II) in 95-96% yield. Thus cellulose is a polyanhydroglucose. When cellulose is subjected to acetolysis (i.e., simultaneous acetylation and hydrolysis) by treatment with a mixture of acetic anhydride and concentrated sulphuric acid, cellobiose octa-acetate is formed. Thus the structure of cellulose is based on the cellobiose unit. Cellobiose is known to be the disaccharide, 4-0-j3-D-glucopyranosyl-D-glucopyranose (III). Finally, very careful acetolysis of cellulose produces a cellotriose, a ceUotetraose and a cellopentaose and in each of these all the 1,4-links have been shown to be j3-links (from calculations of the... 

Figure 3 Molecular structure of cellulase, which incorporates cellotriose (drawn by red and purple) in the so-called cleft, used for the artificial enzymatic polymerization to cellulose. From Davies, G. J. Dauter, M. Brzozowski, M. etal. Biochemistry 37,1926-1932. ...

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