THE STRUCTURE AND RESISTANCE TO METHYLATION OF 1,2-β-GLUCANS FROM SPECIES OF AGROBACTERIA

1961 ◽  
Vol 39 (5) ◽  
pp. 1067-1073 ◽  
Author(s):  
P. A. J. Gorin ◽  
J. F. T. Spencer ◽  
D. W. S. Westlake
Keyword(s):  
Plant Pathogens ◽  
Dimethyl Sulphate ◽  
Linear Structure ◽  
Extracellular Polysaccharides ◽  
Dimethyl Formamide ◽  
Hydroxyl Groups ◽  
Partial Acid Hydrolysis ◽  
Sodium Borohydride Reduction ◽  
Chain Lengths ◽  
Hydrolysis Of

The structures of extracellular polysaccharides produced by the plant pathogens Agrobacterium tumefaciens (2 strains), A. rhizogenes, A. radiobacter, A. ruhi, A. gypsophilae, and A. pseudotsugae were investigated. Polymeric material was formed in good yield from all organisms except A. gypsophilae. Periodate oxidations of the polysaccharides and their sodium borohydride reduction products indicated linear 1,2-glucopyranose structures for A. tumefaciens (2 strains), A. rhizogenes, A. radiobacter, and A. rubi polymers. Optical rotational considerations led to the assignment of β-configurations. The linear structure for the A. radiobacter polysaccharide was confirmed by the isolation, after partial acid hydrolysis, of five 1,2-linked oligosaccharides with chain lengths of two to six. Periodate and chromatographic data indicated that the polysaccharide from A. pseudotsugae contained glucose and galactose and 1,6- as well as 1,2-glycopyranose links. It is noteworthy that the polysaccharides from the genus Agrobacteriurm are shown to be mainly 1,2-β-glucans, a structure not yet found in other genera.Treatment of linear 1,2-β-glucans from A. tumefaciens, A. radiobacter, and A. rhizogenes with sodium hydroxide – dimethyl sulphate, followed by silver oxide in methyl iodide dimethyl formamide, did not cause full methylation. Some of the 3-hydroxyl groups were not substituted and possible reasons for this unreactivity are discussed.

Structure of the extracellular bacterial polysaccharide from Arthrobacter viscosus NRRL B-1973

1968 ◽  
Vol 46 (21) ◽  
pp. 3353-3361 ◽  
Author(s):  
J. H. Sloneker ◽  
Danute G. Orentas ◽  
C. A. Knutson ◽  
P. R. Watson ◽  
Allene Jeanes
Keyword(s):  
Acid Hydrolysis ◽  
Linear Structure ◽  
Sugar Residue ◽  
Hydroxyl Groups ◽  
Bacterial Polysaccharide ◽  
Sodium Metaperiodate ◽  
Mannuronic Acid ◽  
Arthrobacter Viscosus ◽  
Hydrolysis Of

D-Glucose, D-galactose, and D-mannuronic acid in equimolar proportions constitute 75% of the weight of the polysaccharide elaborated by Arthrobacter viscosus NRRL B-1973. O-Acetyl groups account for the remaining 25% of the weight; 50% of the hydroxyl groups are acetylated. Acid hydrolysis of the polysaccharide revealed that the D-mannopyranosyluronic acid bonds hydrolyzed with unexpected ease. Controlled acid hydrolysis afforded three oligosaccharides identified as 4-O-β-D-glucopyranosyl-D-galactose; 4-O-β-D-mannopyranosyluronic acid-D-glucose; and O-β-D-mannopyranosyluronic acid-(1 → 4)-O-β-D-glucopyranosyl-(1 → 4)-D-galactose. The native polysaccharide was oxidized slowly by sodium metaperiodate and consumed 0.42 mole per sugar residue in 340 h at 4°. The deacetylated polysaccharide consumed 0.67 mole of periodate per sugar residue and produced 1 mole of acid per 160 to 165 sugar residues in 170 h at 4°. At 20° the deacetylated polysaccharide was oxidized excessively by periodate, 1.5 moles of oxidant was consumed, and 0.4 mole of acid was produced per sugar residue in 340 h. However, only 20% of the C4-substituted D-glucose residues in the polysaccharide was cleaved by periodate in spite of the excessive oxidation at 20°.The polysaccharide has a linear structure and consists predominantly of repeating trisaccharide units, O-β-D-mannopyranosyluronic acid-(1 → 4)-O-β-D-glucopyranosyl-(1 → 4)-D-galactose.

Studies on the Lignin of Eucalyptus regnans. III. The Isolation of an Alkali Lignin from Sulphate Pulping

1949 ◽  
Vol 2 (1) ◽  
pp. 117
Author(s):  
JWT Merewether
Keyword(s):  
Acetic Anhydride ◽  
Alkaline Hydrolysis ◽  
Empirical Formula ◽  
Benzoyl Chloride ◽  
Dimethyl Sulphate ◽  
Hydroxyl Groups ◽  
Equivalent Weight ◽  
Eucalyptus Regnans ◽  
Alkali Lignin ◽  
Hydrolysis Of

An alkali lignin containing no sulphur has been obtained as a by-product from the sulphate pulping of Eucalyptus regnans. Like other alkali lignins it contains hydroxyl groups, both acidic and alcoholic, as well as methoxyl groups. Acetic anhydride in pyridine yields an octoacetyl derivative which is readily hydrolysed by boiling water to a heptacetyl derivative. In pyridine, benzoyl chloride yields an octobenzoyl derivative while in aqueous alkali it yields a hexabenzoyl compound. Dimethyl sulphate yields a heptamethyl alkali lignin, diazomethane a hexamethyl derivative, while cold alkaline hydrolysis of the latter gives a pentamethyl derivative, and hot alkaline hydrolysis yields an anhydrotrimethyl alkali lignin. One of the methoxyl groups formed by methylation is unstable to acetylation by acetic anhydride in pyridine, heptamethyl alkali lignin yielding a hexamethyldiacetyl derivative, hexamethyl alkali lignin a pentamethyltriacetyl derivative, pentamethyl alkali lignin a tetramethyltetracetyl derivative, and anhydrotrimethyl alkali lignin the corresponding anhydrodimethyltetracetyl alkali lignin. Triphenylchloromethane in pyridine yields a monotrityl derivative.p-Nitrophenylhydrazine gives a di-p-nitrophenylhydrazone and phenylhydrazine a phenylhydrazone-osazone. Potentiometric titration shows two points of inflection and an equivalent weight of 863. The data are consistent with the empirical formula C92Hl04O34(1754) or C73H54O9,(OCH3)14,(OH)3,C(OH),CO-CH20H,C0,COOH

scholarly journals Adjustment of Hydrophobic Properties of Cellulose Materials

Polymers ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1241
Author(s):  
Michael Ioelovich
Keyword(s):  
Ester Group ◽  
Hydroxyl Groups ◽  
Chemical Methods ◽  
Hydrophobic Properties ◽  
Cellulose Esters ◽  
Cellulose Modification ◽  
Polar Groups ◽  
Polar Substituents ◽  
Hydrolysis Of ◽  
Cellulose Materials

In this study, physicochemical and chemical methods of cellulose modification were used to increase the hydrophobicity of this natural semicrystalline biopolymer. It has been shown that acid hydrolysis of the initial cellulose increases its crystallinity, which improves hydrophobicity, but only to a small extent. A more significant hydrophobization effect was observed after chemical modification by esterification, when polar hydroxyl groups of cellulose were replaced by non-polar substituents. The esterification process was accompanied by the disruption of the crystalline structure of cellulose and its transformation into the mesomorphous structure of cellulose esters. It was found that the replacement of cellulose hydroxyls with ester groups leads to a significant increase in the hydrophobicity of the resulting polymer. Moreover, the increase of the number of non-polar groups in the ester substituent contributes to rise in hydrophobicity of cellulose derivative. Depending on the type of ester group, the hydrophobicity increased in the following order: acetate < propionate < butyrate. Therefore, tributyrate cellulose (TBC) demonstrated the most hydrophobicity among all studied samples. In addition, the mixed ester, triacetobutyrate cellulose (TAB), also showed a sufficiently high hydrophobicity. The promising performance properties of hydrophobic cellulose esters, TBC and TAB, were also demonstrated.

The synthesis of Cyclododecane-r-1,c-5,c-9-triamine and r-1,c-5,c-9-Tris(2,3-dimethoxybenzamido)cyclododecane

1975 ◽  
Vol 28 (3) ◽  
pp. 673 ◽  
Author(s):  
DJ Collins ◽  
C Lewis ◽  
JM Swan
Keyword(s):  
Aqueous Solution ◽  
Acid Hydrolysis ◽  
Sulphuric Acid ◽  
Sodium Carbonate ◽  
Sodium Azide ◽  
Room Temperature ◽  
Dimethyl Formamide ◽  
Lithium Aluminium Hydride ◽  
Lithium Aluminium ◽  
Hydrolysis Of

Treatment of cyclododecane-r-1,c-5,c-9-triyl tris(p-toluenesulphonate) with sodium azide in dimethyl-formamide at 100� for 6 h gave the corresponding cis,cis-triazide which upon hydrogenation or reduction with lithium aluminium hydride gave cyclododecane-r-1,c-5,c-9-triamine, isolated as the tris-salicylidene derivative. Acid hydrolysis of this, removal of the salicylaldehyde, and treatment of the aqueous solution with sodium carbonate and 2,3-dimethoxybenzoyl chloride gave r-1,c-5,c- 9-tris(2,3-dimethoxybenzamido)cyclododecane. ��� Treatment of (E,E,E)-cyclododeca-1,5,9-triene with an excess of acetonitrile and sulphuric acid at room temperature for three days gave 18% of (E,E)-1-acetamidocyclododeca-4,8-diene; no di- or tri-amides were isolated.

scholarly journals Study of the mode of action of a polygalacturonase from the phytopathogen Burkholderia cepacia

2007 ◽  
Vol 407 (2) ◽  
pp. 207-217 ◽  
Author(s):  
Claudia Massa ◽  
Mads H. Clausen ◽  
Jure Stojan ◽  
Doriano Lamba ◽  
Cristiana Campa
Keyword(s):  
Mode Of Action ◽  
Burkholderia Cepacia ◽  
Time Course ◽  
Glycoside Hydrolase Family ◽  
Enzymatic Mechanism ◽  
Processive Enzyme ◽  
Chain Lengths ◽  
Methylation Patterns ◽  
Hydrolysis Of ◽  
Hydrolase Family

We have recently isolated and heterologously expressed BcPeh28A, an endopolygalacturonase from the phytopathogenic Gram-negative bacterium Burkholderia cepacia. Endopolygalacturonases belong to glycoside hydrolase family 28 and are responsible for the hydrolysis of the non-esterified regions of pectins. The mode of action of BcPeh28A on different substrates has been investigated and its enzymatic mechanism elucidated. The hydrolysis of polygalacturonate indicates that BcPeh28A is a non-processive enzyme that releases oligomers with chain lengths ranging from two to eight. By inspection of product progression curves, a kinetic model has been generated and extensively tested. It has been used to derive the kinetic parameters that describe the time course of the formation of six predominant products. Moreover, an investigation of the enzymatic activity on shorter substrates that differ in their overall length and methylation patterns sheds light on the architecture of the BcPeh28A active site. Specifically the tolerance of individual sites towards methylated saccharide units was rationalized on the basis of the hydrolysis of hexagalacturonides with different methylation patterns.

STRUCTURE OF THE EXTRACELLULAR POLYSACCHARIDE PRODUCED BY XANTHOMONAS ORYZAE

1962 ◽  
Vol 40 (12) ◽  
pp. 2204-2213 ◽  
Author(s):  
A. Misaki ◽  
S. Kirkwood ◽  
J. V. Scaletti ◽  
F. Smith
Keyword(s):  
Acid Hydrolysis ◽  
Glucuronic Acid ◽  
Periodate Oxidation ◽  
Extracellular Polysaccharide ◽  
Xanthomonas Oryzae ◽  
Sodium Borohydride Reduction ◽  
Glycoside Hydrolysis ◽  
Hydrolysis Of ◽  
Structural Significance ◽  
Molecular Proportion

The extracellular polysaccharide isolated from cultures of Xanthomonas oryzae is composed of D-glucose (5 molecular proportions), D-glucuronic acid (2 molecular proportions), and D-mannose (5 molecular proportions). Acid hydrolysis of this polysaccharide, which contains 0.3% combined pyruvic acid, yields 2-O-β-D-glucopyranosyluronic acid D-mannose, which has been characterized as its crystalline fully methylated β-glycoside. Hydrolysis of the methylated polysaccharide gives 2,3,4,6-tetra-O-methyl-D-mannose (3 molecular proportions), 2,3,4-tri-O-methyl-D-glucuronic acid (1 molecular proportion), 2,3,6-tri-O-methyl-D-glucose (4 molecular proportions), 3,4,6-tri-O-methyl-D-mannose (2 molecular proportions), 2,6-di-O-methyl-D-glucose (3 molecular proportions), 2,3-di-O-methyl-D-glucose (1 molecular proportion). The polyalcohol derived from the polysaccharide by periodate oxidation followed by sodium borohydride reduction gives upon acid hydrolysis glycerol (2 molecular proportions), erythritol (1 molecular proportion), and D-glucose (1 molecular proportion). The general structural significance of these findings is discussed.

Phosphopeptides Obtained by Partial Acid Hydrolysis of α-Casein2

1957 ◽  
Vol 79 (10) ◽  
pp. 2559-2565 ◽  
Author(s):  
N. J. Hipp ◽  
M. L. Groves ◽  
T. L. McMeekin
Keyword(s):  
Acid Hydrolysis ◽  
Partial Acid Hydrolysis ◽  
Hydrolysis Of

scholarly journals Chemical and physical properties of an arabinogalactan-peptide from wheat endosperm

1974 ◽  
Vol 139 (3) ◽  
pp. 535-545 ◽  
Author(s):  
G. B. Fincher ◽  
W. H. Sawyer ◽  
B. A. Stone
Keyword(s):  
Optical Rotation ◽  
Subcellular Location ◽  
Successive Treatment ◽  
Partial Acid Hydrolysis ◽  
Wheat Endosperm ◽  
Anomeric Configuration ◽  
Molecular Core ◽  
Tentative Model ◽  
And Function ◽  
Hydrolysis Of

1. An arabinogalactan-peptide from wheat endosperm was studied by using physicochemical techniques and some aspects of its chemical structure were determined. 2. The arabinogalactan-peptide is a non-associating, polydisperse macromolecule ([unk]=22000) which exhibits only minor non-ideal effects in aqueous solution. 3. Examination of the products of partial acid hydrolysis of the polysaccharide component showed that arabinose is present in the α-l-arabinofuranosyl configuration, and i.r.-absorption spectroscopy and optical-rotation studies suggest that the d-galactopyranose residues are linked by glycosidic linkages in the β-anomeric configuration. 4. The arabinogalactan is linked to a peptide which represents 8% (w/w) of the arabinogalactan-peptide and which may be present as a molecular core. Partial degradation of the polymer by successive treatment with oxalic acid and NaOH showed that the linkage between polysaccharide and peptide involves galactose and hydroxyproline residues and is glycosidic in nature. A tentative model is proposed for the structure of the wheat endosperm arabinogalactan-peptide. 5. The subcellular location and function of the arabinogalactan-peptide is discussed in relation to previous work with related molecules.

THE PROBLEM OF PLASTEIN FORMATION: II. THE CHEMICAL CHANGES INVOLVED IN PLASTEIN FORMATION BY PAPAIN AND BY PEPSIN

1940 ◽  
Vol 18b (9) ◽  
pp. 272-280 ◽  
Author(s):  
H. B. Collier
Keyword(s):  
Enzymatic Hydrolysis ◽  
Free Amino ◽  
Essential Role ◽  
Phenolic Hydroxyl ◽  
Carboxyl Groups ◽  
Hydroxyl Groups ◽  
Chemical Changes ◽  
Phenolic Hydroxyl Groups ◽  
Hydrolysis Of

It has been confirmed that free amino and carboxyl groups disappear during plastein formation from concentrated proteose by crystalline pepsin. Using papain, the changes are obscured by simultaneous hydrolysis. Enzymatic hydrolysis of the plasteins results in the liberation of free amino and carboxyl groups.Reactive "tyrosine" decreases during plastein formation by either enzyme. The same groups are liberated on enzymatic hydrolysis of the plasteins, in a manner analogous to that which takes place in the hydrolysis of typical proteins.It is concluded that in so far as the changes in amino, carboxyl, and "tyrosine" groups are concerned, the plasteins are similar to typical proteins. It is further suggested that the phenolic hydroxyl groups of tyrosine play an essential role in the structure of the protein molecule.Benzaldehyde was found to have no effect on the formation of plastein from proteose by crystalline pepsin.

Studies on the lignin of Eucalyptus regnans F. Muell. VII. The acid hydrolysis of ethanyol lignin-A

1953 ◽  
Vol 6 (2) ◽  
pp. 156 ◽  
Author(s):  
JWT Merewether
Keyword(s):  
Hydrochloric Acid ◽  
Acid Hydrolysis ◽  
Carbonyl Group ◽  
Dilute Hydrochloric Acid ◽  
Hydroxyl Groups ◽  
Eucalyptus Regnans ◽  
Ethoxyl Group ◽  
Hydrolysis Of

Ethanol lignin-A from the ethanolysis of Eucalyptus regnans P. Muell. has been hydrolysed with dilute hydrochloric acid with the object of ascertaining whether the combined ethoxyl is present as an acetal or as ether. Hydrolysis with 12 per cent. hydrochloric acid was found to split off one ethoxyl group, while hydrolysis with 20 per cent. acid brought about complete de-ethylation. The de-ethylated ethanol lignin-A contained one carbonyl group less and two hydroxyl groups more than the original ethanol lignin-A. These results lend no support to the hypothesis that alcohol lignins are acetals, and favour the theory that the combined alkoxyl is probably present as ether.

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