Carboxymethyl cellulase

Enzyme preparations active against crystalline cellulose, marble-milled filter paper, carboxymethylcellulose (CM-cellulose), hemicellulose, and D-xylan have been obtained from cultures of Ruminococcus flavefaciens. Carboxymethyl cellulase and D-xylanase activities were present in a high molecular weight complex (see p. 461). 

Yucca schidigera and Quillaja saponaria containing 4.4% and 10% saponins (Wang et al. 1998) decreased polysaccharide degrading enzymes (carboxymethyl-cellulase and xylanase) considerably and inhibited protozoa to the extent of 42% and 54% respectively (Hristov et al. 1999, 2003). Wang et al. (1998) studied the effect of yucca extract (0.5 mg/ml buffer) on rumen fermentation in RUSITEC and reported no effect on dry matter digestibility, gas production and volatile fatty acid production, but the protozoa numbers were significantly reduced, while the number of bacteria was not affected. 

Although carboxymethyl cellulase (CMCase) is a cellulose-degrading enzyme, it is involved in cellulose formation in acetic acid bacteria (Tonouchi et al. 1995). In plants, a membrane-bound endo-l,4-beta-glucanase called Korrigan (KOR) is involved in cellulose formation (Sato et al. 2001). In a previous report, the CMCase gene was also shown to be essential for cellulose production (Standal et al. 1994). Nevertheless, a recent study found that a very small amount of particulate material accumulated in the culture of the disrupted strain (Nakai et al. 2013). The particulate material was shown to contain highly twisted ribbons of cellulose. It was also reported that a portion of CMCase is localized to the cell surface (Yasutake... 

Siddiqui, K. S., Saqib, A. A. N., Rashid, M. H., et al. (2000). Carboxyl group modification significantly altered the kinetic properties of purified carboxymethyl-cellulase from Aspergillus niger. Enzyme Microbial Technol, 27, 467-474. 

Fig. 39.—,3C-N.m.r. Spectra of A, 0-(Carboxymethyl)cellulose (d.s. 0.7), Partially Degraded by Cellulase, in D20 at 30° (R, signal of reducing-end residue S represents a 13C nucleus bonded to an alkoxyl group) and of B, 0-(2-Hydroxyethyl)cellulose (d.s. 0.8), Partly Degraded by Cellulase, in D20 at 30°. (R, signal due to reducing-end residue S represents a 13C nucleus bonded to an alkoxyl group.)...

The titers of cellulase activities found in anaerobic digesters, when compared to the few other "hydrolytic environments" for which analytical data are available, are strikingly low. Table III shows such values for filter paper and carboxymethyl cellulose degrading activities. This evidence seems to indicate that the cellulose degrading enzymes in ... 

In previous work, we obtained several cellulase components from culture filtrates of Irpex lacteus (Polyporus tulipiferae) or from Driselase, a commercial enzyme preparation of this fungus they behaved practically as a single protein (1,2,3). They were different in randomness of the hydrolysis of carboxymethyl cellulose (CMC), expressed as the ratio... 

Calculations One Cellulase Unit (CU) is defined as the amount of activity that will produce a relative fluidity change of 1 in 5 min in a defined carboxymethyl cellulose substrate under the conditions of the assay. 

On the other hand, an exo-acting enzyme will bring about only a very marginal reduction in the DP of the polymer for each catalytic event. In tests of cellulases, it is usual to monitor both reducing sugar and viscosity as the enzyme in question hydrolyses carboxymethylated cellulose. 

Effect of Chemical Modification of Cellulose on the Activity of Cellulase. Soluble cellulose derivatives like carboxymethyl and hydroxy-ethyl cellulose have an advantage in being randomly coiled, but they are not without limitations. The two basic problems are those created by... 

In the hydrolysis of O-(carboxymethyl) cellulose with acids, the viscosity-molecular weight relationship deviates from the modified Staud-inger equation in a way analogous to that for other cellulosic materials, and the polysaccharide is hydrolyzed enzymically by cellulase similarly to 0-(2-hydroxyethyl) cellulose, so that the two substituents are equally effective in limiting the enzymic action. 

K. E. Almin and K. E. Eriksson, Influence of carboxymethyl cellulose properties on the determination of cellulase activity in absolute terms, Arch. Biochem. Biophys., 124 (1968) 129-134. 

K. E. Eriksson and B. H. Hollmark, Kinetic studies of the action of cellulase upon sodium carboxymethyl cellulose, Arch. Biochem. Biophys., 133 (1969) 233-237. 

Carbohydrate metabolism Amylases Cellulases Glucosidases Amylopectin azure Carboxymethyl-cellulose Nitrophenyl-a//i-glucosides M U F-cellobiopyranoside MUF-a//i-glucoside... 

Characteristics of the n.m.r. spectra of methyl-, carboxymethyl-, and hydroxyethyl-cellulose ethers have been examined at 22.6 MHz. Partial pre-depolymerization with acid or cellulase proved to be a requisite step. The spectra permitted an assessment of the degree of substitution at individual positions of the D-glucose residues and afforded other information in agreement with data obtained by other methods. 

A jS-D-glucosidase (mol. wt. 4.7 x 10 ) has been isolated from a commercial preparation of cellulase (obtained from culture filtrates of Trichoderma viride) by fractional precipitation with ammonium sulphate, gel filtration, ion-exchange chromatography, and isoelectric focusing. The purified, homogeneous enzyme (p7 5.74) was inactive against microcrystalline cellulose and carboxymethyl-cellulose. Km Values of 0.28, 1.5, and 0.35 mmoll were obtained for 4-nitrophenyl jS-D-glucopyranoside, cellobiose, and cellotetraose, respectively. 

A derivatized form of pneumococcal type III polysaccharide has been used to distinguish between three jS-D-glucan hydrolases (including cellulase) from a Streptomyces species. Oligosaccharides also released from carboxymethyl-cellulose, lichenin, and oat glucan by the enzymes were identified, allowing the substrate specificities of the enzymes to be deduced. 

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