Carboxymethylcellulose towards

Ce4+-initiated graft polymerization with viscose fibre and carboxymethylcellulose (CMC) was studied341. The molecular mass distribution (MMD) of grafted PMMA chains in both cases was described by a unimodal curve with CMC the maximum was shifted towards higher molecular masses because of faster diffusion of the monomer into this material. 

Spherical pellets containing 5% triamcinolone acet-onide were prepared by Villar-Lopez and coworkers byextrusion/spheronization after formulation with microcrystalline cellulose and/or a hydrophilic excipient such as lactose, sodium carboxymethylcellulose, or p-cyclodextrin. Their suitability for coating, with a view toward colonic drug delivery, was assessed in terms of their size, sphericity, and dissolution test... 

D-glucanases (I and II) have been purified and shown to be e/ido-enzymes. Both enzymes attack laminaran, carboxymethylpachyman and lichenin, but have no action towards carboxymethylcellulose. The main products of hydrolysis of laminaran were D-glucose and (1 3)-linked oligosaccharides of DP 2, 3, and 4. D-Glucanases I and II were similar to each other, although they differed in molecular weight and kinetic properties. 

Other examples illustrating the effect of substituent distribution on properties include (1) enzymatic stabihty of hydroxyethylcellulose (HEC) (36,37), (2) salt compatibility of carboxymethylcellulose (38,39), and (3) thermal gelation properties of methylcellulose (40). The enzymatic stabihty of HEC is an example where the actual position of the substituents within the anhydroglucose units is considered important. Increasing substitution at the C-2 position promotes better resistance toward enzymatic cleavage of the polymer chain. Positional distribution is also a factor in the other two examples. 

A celluloytic enzyme isolated from a commercial cellulase preparation from Aspergillus niger, and which contained no carbohydrate, was found to be active towards carboxymethylcellulose but inactive towards cellobiose and 4-nitrophenyl jS-o-glucopyranoside, The enzyme (pH optimum 3.9, mol. wt. 2.6 X 10 by sodium dodecyl sulphate-polyacrylamide gel electrophoresis) according to kinetic studies had groups with pK values between 4.2 and 5.3 involved in the enzyme-substrate complex. 

Three extracellular cellulases have been purified from the cultures of a Cellulomonas species. One was found in solution in the cell-free supernatant and two others were found to be bound to the cellulose added as a carbon source. The free enzyme and one of the cellulose-bound enzymes exhibited binding for Sephadex . The two cellulose-bound enzymes are glycoproteins. All three enzymes behaved as ewffo-cellulases towards soluble carboxymethylcellulose and had little activity on cellulose powder. 

A simple procedure for determining the specificity of jS-o-glucan hydrolases involves the use of pneumococcal type III polysaccharide as a substrate. Whereas cellulase, laminarinase, and lichenase are inactive towards this polysaccharide, the two last enzymes hydrolyse its reduced and esterified form. Comparisons of the activities of the enzymes towards these and other substrates e.g. laminarin, lichenin, carboxymethylcellulose) permit them to be distinguished, provided the oligosaccharides released are identified. 

Whole-cell -D-fructofuranosidase from Saccharomyces pastorianus entrapped in spherical agar pellets can be used for the inversion of sucrose in a complete-mixing reactor, demonstrating that it is not necessary to isolate or to purify an enzyme before immobilization. Up to 25% of the enzymic activity was retained when tomato /3-D-fructofuranosidase was immobilized either by embedding it in polyacrylamide gel or by adsorbing it onto carboxymethylcellulose. Substrates did not release the enzyme from either of the carriers neither was the adsorbed enzyme released at pH values <5. No changes were observed in the pH optimum on embedding the enzyme in polyacrylamide gel, and the values for the embedded and adsorbed enzymes towards sucrose were 1.4 x and 6.9 X 10 mol 1 , respectively. 

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