The action of cellulolytic enzymes on substituted celluloses

Klop, W.; Kooiman, P.

doi:10.1016/s0926-6593(65)80011-x

Cited by 37 publications

(10 citation statements)

References 19 publications

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“…Partial reduction of the peak 5 pentasaccharide with sodium borohydride prior to methylation resulted in the appearance of a peak in the gas chromatogram of the subsequently synthesized partially methylated alditol acetate derivatives which has been identified as 4-0-acetyl-1,2,3,5,6-penta-0-methyl sorbitol ("Results"). Thus, in agreement with the known specificity of endoglucanase (3,14), 4-linked glucose occurs at the reducing end of the pentasaccharide. 5.…”

Section: Isolationsupporting

confidence: 83%

The Structure of Plant Cell Walls

Bauer¹,

Talmadge²,

Keegstra³

et al. 1973

Plant Physiol.

360

131

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The molecular structure, chemical properties, and biological function of the xyloglucan polysaccharide isolated from cell walls of suspension-cultured sycamore (Acer pseudoplatanus) cells are described. The sycamore wall xyloglucan is compared to the extracellular xyloglucan secreted by suspension-cultured sycamore cells into their culture medium and is also compared to the seed "amyloid" xyloglucans.Xyloglucan-or fragments of xyloglucan-and acidic fragments of the pectic polysaccharides are released from endopolygalacturonase-pretreated sycamore walls by treatment of these walls with 8 M urea, endoglucanase, or 0.5 N NaOH. Some of the xyloglucan thus released is found to cochromatograph with the acidic pectic fragments on diethylaminoethyl Sephadex. The chemical or enzymic treatments required for the release of xyloglucan from the walls and the cochromatography of xyloglucan with the acidic pectic fragments indicate that xyloglucan is covalently linked to the pectic polysaccharides and is noncovalently bound to the cellulose fibrils of the svcamore cell wall.The molecular structure of sycamore xyloglucan was characterized by methylation analysis of the oligosaccharides obtained by endoglucanase treatment of the polymer. The struc. ture of the polymer is based on a repeating heptasaccharide unit which consists of 4 residues of 8-1-4-linked glucose and 3 residues of terminal xylose. A single xylose residue is glycosidically linked to carbon 6 of 3 of the glucosyl residues.In the first paper of this series (24), recently developed techniques for the methylation analysis of polysaccharides were used in order to study the structure of the primary cell wall of suspension-cultured sycamore cells and in order to characterize structurally the defined fragments released from these walls by a highly purified endopolygalacturonase. This study indicated

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Section: Isolationsupporting

confidence: 83%

The Structure of Plant Cell Walls

Bauer¹,

Talmadge²,

Keegstra³

et al. 1973

Plant Physiol.

360

131

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“…Let us see which factor determines the extent of eM cellulose conversion under the action of the cellulase complex. In accordance with the contemporary understanding of the phenomenon, a random reaction between endoglucanase and eM cellulose takes place only at the portions of the substrate which are composed of some minimal number of unsubstituted glucoside residues (28). On the other hand, depolymerization of eM cellulose under the effect of exoenzymes, which cleave glucose or cellobiose units from the nonreducing end of the polymer molecule, stops as soon as the successive cleavage reaches the substituted residue.…”

Section: Hydrolysis Of Soluble CM Cellulosementioning

confidence: 63%

“…14 shows that the concentration of other reducing sugars reaches a nearly constant level in a relatively short period of time and remains at this level almost to the end of the reaction. As is known, the incomplete enzymatic conversion of CM cellulose to glucose is determined by the presence of substituted glucoside residues, which hinder the enzyme action (27,28). Let us see which factor determines the extent of eM cellulose conversion under the action of the cellulase complex.…”

Section: Hydrolysis Of Soluble CM Cellulosementioning

confidence: 99%

Enzymatic Conversion of Cellulose to Glucose: Present State of the Art and Potential

Klyosov

Rabinowitch

1980

Enzyme Engineering

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“…The third isolated cellulase, Cel 57, is unique in that it depolymerized and degraded cotton cellulose but did not release reducing sugars from CMC nor did it significantly reduce the viscosity of CMC solutions. CMC might not be a substrate for Cel 57 because the substituted carboxymethyl groups sterically hinder its binding to the cellulose; the extent of enzymatic hydrolysis of CMC decreases as the degree of carboxymethyl substitutions increases (4,16,41). To our knowledge, this is the first report of a cellulase that depolymerizes and solubilizes cotton cellulose by cleaving the internal glycosidic bonds and yet does not degrade the watersoluble derivative CMC.…”

Section: Discussionmentioning

confidence: 92%

Three Native Cellulose-Depolymerizing Endoglucanases from Solid-Substrate Cultures of the Brown Rot Fungus Meruliporia (Serpula) incrassata

Kleman-Leyer

Kirk

1994

Appl Environ Microbiol

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Three extracellular cellulose-depolymerizing enzymes from cotton undergoing decay by the brown rot fungus Merulipona (Serpula) incrassata were isolated by anion-exchange and hydrophobic interaction chromatographies. Depolymerization was detected by analyzing the changes in the molecular size distribution of cotton cellulose by high-performance size-exclusion chromatography. The average degree of polymerization (DP; number of glucosyl residues per cellulose chain) was calculated from the size-exclusion chromatography data. The very acidic purified endoglucanases, Cel 25, Cel 49, and Cel 57, were glycosylated and had molecular weights of 25,200, 48,500, and 57,100, respectively. Two, Cel 25 and Cel 49, depolymerized cotton cellulose and were also very active on carboxymethyl cellulose (CMC). Cel 57, by contrast, significantly depolymerized cotton cellulose but did not release reducing sugars from CMC and only very slightly reduced the viscosity of CMC solutions. Molecular size distributions of cotton cellulose attacked by the three endoglucanases revealed single major peaks that shifted to lower DP positions. A second smaller peak (DP, 10 to 20) was also observed in the size-exclusion chromatograms of cotton attacked by Cel 49 and Cel 57. Under the reaction conditions used, Cel 25, the most active of the cellulases, reduced the weight average DP from 3,438 to 315, solubilizing approximately 20%o of the cellulose. The weight average DP values of cotton attacked under the same conditions by Cel 49 and Cel 57 were 814 and 534; weight losses were 9 and 11%, respectively.

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The action of cellulolytic enzymes on substituted celluloses

Cited by 37 publications

References 19 publications

The Structure of Plant Cell Walls

The Structure of Plant Cell Walls

Enzymatic Conversion of Cellulose to Glucose: Present State of the Art and Potential

Three Native Cellulose-Depolymerizing Endoglucanases from Solid-Substrate Cultures of the Brown Rot Fungus Meruliporia (Serpula) incrassata

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