scholarly journals Study of the mode of action and site-specificity of the endo-(1→4)-β-d-glucanases of the fungus Penicillium pinophilum with normal, 1-3H-labelled, reduced and chromogenic cello-oligosaccharides

1990 ◽  
Vol 266 (2) ◽  
pp. 371-378 ◽  
Author(s):  
K M Bhat ◽  
A J Hay ◽  
M Claeyssens ◽  
T M Wood
Keyword(s):  
Cell Membrane ◽  
Mode Of Action ◽  
Analytical Data ◽  
Degree Of Polymerization ◽  
The Other ◽  
Site Specificity ◽  
Glycosidic Bonds ◽  
Penicillium Pinophilum ◽  
Hydrolysis Of Cellulose ◽  
Hydrolysis Of

The modes of action of the five major endo-(1→4)-beta-D-glucanases (I, II, III, IV and V) purified from Penicillium pinophilum cellulase were compared by h.p.l.c. analysis, with normal, 1-3H-labelled and reduced cello-oligosaccharides and 4-methylumbelliferyl glycosides as substrates. Significant differences were observed in the preferred site of cleavage even when substrates with the same number of glycosidic bonds were compared. Thus, although endoglucanase I was unable to attack normal cello-oligosaccharides shorter than degree of polymerization 6, it hydrolysed reduced cellopentaose to yield cellotriose and cellobi-itol, and it produced cellotriose and 4-methylumbelliferyl glucoside from 4-methylumbelliferyl cellotetraoside. Endoglucanase IV hydrolysed [1-3H]cellotriose but did not attack either cellotri-itol or 4-methylumbelliferyl cellobioside. These and other anomalous results indicated clearly that modification of the reducing glycosyl residue on the cello-oligosaccharides induces in an apparent change in the mode of action of the endoglucanases. It is suggested that, although cello-oligosaccharide derivatives are useful for differentiating and classifying endoglucanases, conclusions on the mechanism of cellulase action resulting from these measurements should be treated cautiously. Unequivocal information on the mode of endoglucanase action on cello-oligosaccharides was obtained with radiolabelled cello-oligosaccharides of degree of polymerization 3 to 5. Indications that transglycosylation was a property of the endoglucanases were particularly evident with the 4-methylumbelliferyl cello-oligosaccharides. Turnover numbers for hydrolysis of the umbelliferyl cello-oligosaccharides were calculated, and these, along with the other analytical data collected on the products of hydrolysis of the normal, reduced and radiolabelled cello-oligosaccharides, suggested that the various endoglucanases had different roles to play in the overall hydrolysis of cellulose to sugars small enough to be transported through the cell membrane.

Efficient Hydrolytic Breakage of β-1,4-Glycosidic Bond Catalyzed by a Difunctional Magnetic Nanocatalyst

2018 ◽  
Vol 71 (8) ◽  
pp. 559 ◽  
Author(s):  
Ren-Qiang Yang ◽  
Ni Zhang ◽  
Xiang-Guang Meng ◽  
Xiao-Hong Liao ◽  
Lu Li ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Reaction Time ◽  
Microcrystalline Cellulose ◽  
Significant Loss ◽  
Reducing Sugar ◽  
Magnetic Nanocatalyst ◽  
Efficient Catalyst ◽  
Glycosidic Bonds ◽  
Hydrolysis Of Cellulose ◽  
Hydrolysis Of

A novel difunctional magnetic nanocatalyst (DMNC) was prepared and used to catalyse the hydrolytic breakage of β-1,4-glycosidic bonds. The functional nanoparticle displayed excellent catalytic activity for hydrolysis of cellobiose to glucose under moderate conditions. The conversion of cellobiose and yield of glucose could reach 95.3 and 91.1 %, respectively, for a reaction time of 6 h at pH 4.0 and 130°C. DMNC was also an efficient catalyst for the hydrolysis of cellulose: 53.9 % microcrystalline cellulose was hydrolyzed, and 45.7 % reducing sugar was obtained at pH 4.0 and 130°C after 10 h. The magnetic catalyst could be recycled and reused five times without significant loss of catalytic activity.

Cellulose Hydrolysis by Acidic Ionic Liquids Enhanced with Microwave Heating

2018 ◽  
Vol 1145 ◽  
pp. 75-79 ◽  
Author(s):  
Hai Yun Ma ◽  
Zhi Ping Zhao ◽  
Peng Lu
Keyword(s):  
Ionic Liquids ◽  
Microwave Heating ◽  
Reducing Sugars ◽  
Cellulose Hydrolysis ◽  
Degree Of Polymerization ◽  
Deionized Water ◽  
Acidic Ionic Liquids ◽  
Hydrolysis Of Cellulose ◽  
Total Reducing Sugars ◽  
Hydrolysis Of

The hydrolysis of cellulose into platform compounds and chemicals fuels has gained much attention to relieve the global energy crisis and environmental pollution. The filter paper (FP) cellulose with average degree of polymerization (DP) of 1000-1300 was dissolved in 1-butyl-3-methylimidazolium chloride ([BMIM]Cl) firstly. And then acidic ionic liquids (ILs), ([(CH2)3SO3HVIm]HSO4) as the catalyst was applied to hydrolyze the FP cellulose by microwave heating. Compared with the oil bath heating method, microwave heating could effectively increase the total reducing sugars (TRS) yield about 10.7%. When the ratio of ILs catalyst to FP (w/w) was 0.167, and the ratio of deionized water to FP (w/w) was 0.833, the TRS yield was up to 60.8% within 20 min at 100°C.

Mode of Action and Partial Purification of the Active Centre of exo-Poly-α-D-galacturonosidase from Selenomonas ruminantium

1993 ◽  
Vol 58 (3) ◽  
pp. 681-692
Author(s):  
Kveta Heinrichová ◽  
Július Heinrich ◽  
Mária Dzúrová ◽  
Alexander Ziolecki
Keyword(s):  
Mode Of Action ◽  
Kinetic Data ◽  
Degree Of Polymerization ◽  
Partial Purification ◽  
Catalytic Hydrolysis ◽  
Product Analysis ◽  
Active Centre ◽  
Selenomonas Ruminantium ◽  
Michaelis Constants ◽  
Hydrolysis Of

In the presented paper are summarized results of the study of the mode of action, dimensions and arrangement of the active centre of the exo-poly-α-D-galacturonosidase, (poly(1,4-α-D-galactosiduronate) digalacturonohydrolase, E.C. 3.2.1.82) produced by the bacteria Selenomonas ruminantium. With this aim we determined experimentally values of Michaelis constants and limiting rates for the catalytic hydrolysis of linear oligo(D-galactosiduronates) of the degree of polymeration in the range of 3 to 8, at pH 7.0 and the temperature 30 °C. We calculated molecular activities k0 and parameters k0/Km from these values. From the dependence of logk0 and logk0/Km on the degree of polymerization five subsites of the active centre were determined, with the catalytic site being situated between the second and third one. Kinetic data were used for the calculation of the affinities of the fourth and fifth subsites A4 and A5 in accordance with the theory of Hiromi. Product analysis of non-labelled oligo(D-galactosiduronates) and compounds labelled with [1-3H] at the reducing end anabled to ascertain approximately the value for the first subsite A1 of the active centre and to study the mode of action of the exo-poly-α-D-galacturonosidase from Selenomonas ruminantium.

scholarly journals Fungal cellulase systems. Comparison of the specificities of the cellobiohydrolases isolated from Penicillium pinophilum and Trichoderma reesei

1989 ◽  
Vol 261 (3) ◽  
pp. 819-825 ◽  
Author(s):  
M Claeyssens ◽  
H Van Tilbeurgh ◽  
P Tomme ◽  
T M Wood ◽  
S I McRae
Keyword(s):  
Trichoderma Reesei ◽  
Specific Binding ◽  
Degree Of Polymerization ◽  
Penicillium Pinophilum ◽  
Random Manner ◽  
Chromophoric Group ◽  
Apparent Kinetic Parameters ◽  
Fungal Cellulase ◽  
Hydrolysis Of ◽  
Reaction Patterns

Reaction patterns for the hydrolysis of chromophoric glycosides from cello-oligosaccharides and lactose by the cellobiohydrolases (CBH I and CBH II) purified from Trichoderma reesei and Penicillium pinophilum were determined. They coincide with those found for the parent unsubstituted sugars. CBH I enzyme from both organisms attacks these substrates in a random manner. Turnover numbers are, however, low and do not increase appreciably as a function of the degree of polymerization of the substrates. The active-site topology of the CBH I from T. reesei was further probed by equilibrium binding experiments with cellobiose, cellotriose, lactose and some of their derivatives. These point to a single interaction site (ABC), spatially restricted as deduced from the apparent independency of the thermodynamic parameters. It appears that the putative subsite A can accommodate a galactopyranosyl or glucopyranosyl group, and subsite B a glucopyranosyl group, whereas in subsite C either a glucopyranosyl or a chromophoric group can be bound, scission occurring between subsites B and C. The apparent kinetic parameters (turnover numbers) for the hydrolysis of cello-oligosaccharides (and their derivatives) by the CBH II type enzyme increase as a function of chain length, indicative of an extended binding site (A-F). Its architecture allows for specific binding of beta-(1-4)-glucopyranosyl groups in subsites A, B and C. Binding of a chromophore in subsite C produces a non-hydrolysable complex. The thermodynamic interaction parameters of some ligands common to both type of enzyme were compared: these substantiate the conclusions reached above.

CONSTITUTION OF THE HEMICELLULOSE FROM MESTA FIBER (HIBISCUS CANNABINUS)

1963 ◽  
Vol 41 (9) ◽  
pp. 2346-2350 ◽  
Author(s):  
S. K. Sen
Keyword(s):  
Molecular Weight ◽  
Uronic Acid ◽  
Average Molecular Weight ◽  
Analytical Data ◽  
Degree Of Polymerization ◽  
Hibiscus Cannabinus ◽  
Molar Ratio ◽  
Alkaline Solutions ◽  
Number Average Molecular Weight ◽  
Hydrolysis Of

The chlorite holocellulose of mesta fiber (Hibiscus cannabinus) was extracted with alkaline solutions of successively increasing concentration and finally with alkaline borate solution. Hemicellulose fractions (I–IV) were thus obtained. Analytical data are recorded for each fraction.Partial acid hydrolysis of the mesta hemicellulose gave 2-O-(4-O-methyl-α-D-glucopyranosyl uronic acid)-D-xylopyranose. Methanolysis and hydrolysis of the fully methylated hemicellulose (fraction II) gave a mixture of 3-O-methyl-D-xylose, 2,3-di-O-methyl-D-xylose, 2,3,4-tri-O-methyl-D-xylose, and 2-O-(2,3,4-tri-O-methyl-α-D-glucopyranosyl uronic acid)-3-O-methyl-D-xylopyranose in the approximate molar ratio of 1.6:34:1:6.4. The number-average molecular weight of the methylated polysaccharide was 18,400 ± 500 (degree of polymerization, 110 ± 3). The number-average molecular weight of the original hemicellulose (fraction II) was found to be 23,000 ± 500 (degree of polymerization, 164 ± 3). On the basis of this and other evidences it is suggested that the polysaccharide is composed of chains of 144 (1 → 4)-linked β-D-xylopyranose residues having approximately every seventh residue carrying a terminal 4-O-methyl-α-D-glucuronic acid residue linked through position 2. A small degree of branching in the backbone of D-xylose is indicated.

scholarly journals Serratia marcescens chitobiase is a retaining glycosidase utilizing substrate acetamido group participation

1997 ◽  
Vol 328 (3) ◽  
pp. 945-949 ◽  
Author(s):  
Sophie DROUILLARD ◽  
Sylvie ARMAND ◽  
J. Gideon DAVIES ◽  
E. Constantin VORGIAS ◽  
Bernard HENRISSAT
Keyword(s):  
Serratia Marcescens ◽  
Catalytic Mechanism ◽  
Degree Of Polymerization ◽  
Hplc Separation ◽  
Group Participation ◽  
Anomeric Configuration ◽  
Early Stages ◽  
Glycosidic Bonds ◽  
Hydrolysis Of

The stereochemistry of the reaction catalysed by Serratia marcescens chitobiase was determined by HPLC separation of the anomers of N-acetylglucosamine produced during the hydrolysis of p-nitrophenyl N-acetyl-β-D-glucosaminide (PNP-GlcNAc). In the early stages of the reaction, the β-anomer was found to prevail, whereas the α-anomer dominated at mutarotation equilibrium. This established that chitobiase hydrolyses glycosidic bonds with overall retention of the anomeric configuration. Chitobiase-catalysed hydrolysis of PNP-GlcNAc was competitively inhibited by a series of chito-oligosaccharides (degree of polymerization 2-5) that were selectively de-N-acetylated at their non-reducing end. The results are in accord with the participation of the acetamido group at C-2 of the substrate in the catalytic mechanism of chitobiase and related enzymes.

scholarly journals Cooperation of hydrolysis modes among xylanases reveals the mechanism of hemicellulose hydrolysis by Penicillium chrysogenum P33

2019 ◽  
Vol 18 (1) ◽  
Author(s):  
Yi Yang ◽  
Jinshui Yang ◽  
Ruonan Wang ◽  
Jiawen Liu ◽  
Yu Zhang ◽  
...  
Keyword(s):  
Synergistic Effect ◽  
Penicillium Chrysogenum ◽  
Synergistic Effects ◽  
Degree Of Polymerization ◽  
Glycosidic Bonds ◽  
Cazy Database ◽  
Complete Set ◽  
First Time ◽  
Hydrolysis Of ◽  
Gh10 Family

Abstract Background Xylanases randomly cleave the internal β-1,4-glycosidic bonds in the xylan backbone and are grouped into different families in the carbohydrate-active enzyme (CAZy) database. Although multiple xylanases are detected in single strains of many filamentous fungi, no study has been reported on the composition, synergistic effect, and mode of action in a complete set of xylanases secreted by the same microorganism. Results All three xylanases secreted by Penicillium chrysogenum P33 were expressed and characterized. The enzymes Xyl1 and Xyl3 belong to the GH10 family and Xyl3 contains a CBM1 domain at its C-terminal, whereas Xyl2 belongs to the GH11 family. The optimal temperature/pH values were 35 °C/6.0, 50 °C/5.0 and 55 °C/6.0 for Xyl1, Xyl2, and Xyl3, respectively. The three xylanases exhibited synergistic effects, with the maximum synergy observed between Xyl3 and Xyl2, which are from different families. The synergy between xylanases could also improve the hydrolysis of cellulase (C), with the maximum amount of reducing sugars (5.68 mg/mL) observed using the combination of C + Xyl2 + Xyl3. Although the enzymatic activity of Xyl1 toward xylan was low, it was shown to be capable of hydrolyzing xylooligosaccharides into xylose. Xyl2 was shown to hydrolyze xylan to long-chain xylooligosaccharides, whereas Xyl3 hydrolyzed xylan to xylooligosaccharides with a lower degree of polymerization. Conclusions Synergistic effect exists among different xylanases, and it was higher between xylanases from different families. The cooperation of hydrolysis modes comprised the primary mechanism for the observed synergy between different xylanases. This study demonstrated, for the first time, that the hydrolysates of GH11 xylanases can be further hydrolyzed by GH10 xylanases, but not vice versa.

Mode of Action of Exo- and Endo-Type Cellulases from Irpex lacteus in the Hydrolysis of Cellulose with Different Crystallinities

1993 ◽  
Vol 114 (2) ◽  
pp. 230-235 ◽  
Author(s):  
Eiichi Hoshino ◽  
Yasushi Sasaki ◽  
Mituo Okazaki ◽  
Kazutosi Nisizawa ◽  
Takahisa Kanda
Keyword(s):  
Mode Of Action ◽  
Irpex Lacteus ◽  
Hydrolysis Of Cellulose ◽  
Hydrolysis Of

A FACILE SYNTHESIS AND REACTIONS OF AMINO SELENOLO[2,3-b]PYRIDINE CARBOXYLATE

2015 ◽  
Vol 12 (1) ◽  
pp. 3910-3918 ◽  
Author(s):  
Dr Remon M Zaki ◽  
Prof Adel M. Kamal El-Dean ◽  
Dr Nermin A Marzouk ◽  
Prof Jehan A Micky ◽  
Mrs Rasha H Ahmed
Keyword(s):  
Biological Activity ◽  
Carbonyl Compounds ◽  
Mass Spectra ◽  
The Other ◽  
Pyridine Derivatives ◽  
Facile Synthesis ◽  
High Biological Activity ◽  
Basic Hydrolysis ◽  
Pyridine Carboxylate ◽  
Hydrolysis Of

 Incorporating selenium metal bonded to the pyridine nucleus was achieved by the reaction of selenium metal with 2-chloropyridine carbonitrile 1 in the presence of sodium borohydride as reducing agent. The resulting non isolated selanyl sodium salt was subjected to react with various α-halogenated carbonyl compounds to afford the selenyl pyridine derivatives 3a-f  which compounds 3a-d underwent Thorpe-Ziegler cyclization to give 1-amino-2-substitutedselenolo[2,3-b]pyridine compounds 4a-d, while the other compounds 3e,f failed to be cyclized. Basic hydrolysis of amino selenolo[2,3-b]pyridine carboxylate 4a followed by decarboxylation furnished the corresponding amino selenolopyridine compound 6 which was used as a versatile precursor for synthesis of other heterocyclic compound 7-16. All the newly synthesized compounds were established by elemental and spectral analysis (IR, 1H NMR) in addition to mass spectra for some of them hoping these compounds afforded high biological activity.

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