CHARACTERIZATION OF THREE HEMICELLULOSES FROM THE WOOD OF AMABILIS FIR (ABIES AMABILIS)

1963 ◽  
Vol 41 (6) ◽  
pp. 1381-1388 ◽  
Author(s):  
E. C. A. Schwarz ◽  
T. E. Timell
Keyword(s):  
Periodate Oxidation ◽  
Specific Rotation ◽  
Water Soluble ◽  
Partial Hydrolysis ◽  
Abies Amabilis ◽  
A Value ◽  
Linear Framework ◽  
Molecular Rotations ◽  
Hydrolysis Of

An arabino-4-O-methylglucuronoxylan (10:14:76), a water-soluble galactoglucomannan (1:1:3), and an alkali-soluble galactoglucomannan (0.1:1:3) have been isolated in yields of 7, 4, and 8% from the wood of amabilis fir (Abies amabilis). The structure of the polysaccharides was established by methylation and periodate oxidation techniques. The xylan ([Formula: see text]) contained side chains of (1 → 2)-linked 4-O-methyl-α-D-glucuronic acid and (1 → 3)-linked α-L-arabinofuranose residues, both attached directly to a linear framework of (1 → 4)-linked β-D-xylose residues. The galactoglucomannans ([Formula: see text] 76 and 95) contained (1 → 6)-linked α-D-galactopyranosyl residues attached directly to a backbone of (1 → 4)-linked β-D-mannose and β-D-glucose residues. Partial hydrolysis of the two hexosans yielded 10 and 13 oligosaccharides, respectively, containing (1 → 4)-β-D-mannose, (1 → 4)-β-D-glucose, and (1 → 6)-α-D-galactopyranose residues. The molecular rotations of a series of mannooligosaccharides corresponded to a value of −54° for the specific rotation of an infinitely long mannan. It is concluded that the main hemicelluloses in amabilis fir wood are the same as those occurring in the wood of gymnosperms from other genera. The same three hemicelluloses are also present in the bark of this species.

CONSTITUTION OF THREE HEMICELLULOSES FROM THE WOOD OF ENGELMANN SPRUCE (PICEA ENGELMANNI)

1963 ◽  
Vol 41 (6) ◽  
pp. 1389-1395 ◽  
Author(s):  
A. R. Mills ◽  
T. E. Timell
Keyword(s):  
Glucuronic Acid ◽  
Water Soluble ◽  
Partial Hydrolysis ◽  
Side Chains ◽  
Engelmann Spruce ◽  
Linear Framework ◽  
Single Side ◽  
Hydrolysis Of ◽  
Picea Engelmanni

An arabino-4-O-methylglucuronoxylan (10:70:12), a water-soluble galactoglucomannan (1:1:3), and an alkali-soluble galactoglucomannan (0.2:1:3) have been isolated in yields of 8.0, 1.0, and 8.1% from the wood of Engelmann spruce (Picea engelmanni). The xylan consisted of a linear framework of (1 → 4)-linked β-D-xylose residues to which were directly attached single side chains of (1 → 2)-linked 4-O-methyl-α-D-glucuronic acid and (1 → 3)-linked α-L-arabinofuranose residues. The galactoglucomannans were both composed of a backbone of (1 → 4)-linked β-D-mannose and β-D-glucose residues, some of which carried directly attached side chains of (1 → 6)-linked α-D-galactopyranose residues. Partial hydrolysis of the water-soluble galactoglucomannan yielded, among other oligosaccharides, a trisaccharide composed of galactose, glucose, and mannose residues. It is concluded that the main polysaccharides in the wood of Engelmann spruce are the same as those in most other gymnosperms. In the bark of this tree, the water-soluble galactoglucomannan is replaced by one or several polysaccharides of an entirely different composition.

Structure of the Capsular Polysaccharide of Klebsiella K-type 56

1973 ◽  
Vol 51 (18) ◽  
pp. 3021-3026 ◽  
Author(s):  
Yuen-Min Choy ◽  
Guy G. S. Dutton
Keyword(s):  
Uronic Acid ◽  
Capsular Polysaccharide ◽  
Periodate Oxidation ◽  
Side Chain ◽  
Partial Hydrolysis ◽  
Hydrolysis Of

Methylation, periodate oxidation, and partial hydrolysis studies on the capsular polysaccharide of Klebsiella K-type 56 show the structure to be a repeating unit consisting of[Formula: see text]The nature of the anomeric linkages was determined by p.m.r. spectroscopy of isolated oligosaccharides. The position of the L-rhamnose side chain was defined by characterization of the di- and tetrasaccharides obtained by partial hydrolysis of the fully methylated polysaccharide.This structure represents the first capsular polysaccharide lacking uronic acid to be studied in the genus Klebsiella.

CONSTITUTION OF THE GALACTOMANNAN FROM THE KERNEL OF GREEN PALMYRA PALM NUT (BORASSUS FLABELLIFER LINN.)

1961 ◽  
Vol 39 (7) ◽  
pp. 1408-1418 ◽  
Author(s):  
A. K. Mukherjee ◽  
D. Choudhury ◽  
P. Bagchi
Keyword(s):  
Periodate Oxidation ◽  
Structural Formula ◽  
Water Soluble ◽  
Molar Ratio ◽  
Partial Hydrolysis ◽  
Soluble Polysaccharide ◽  
Hydrolysis Of

The water-soluble polysaccharide extracted from the kernel of green palmyra palm nut (Borassusflabellifer Linn.) was shown to be composed of D-galactose and D-mannose in the proportion of 1:2.4. Hydrolysis of the fully methylated galactomannan yielded 2,3,4,6-tetra-O-methyl-D-galactose, 2,3,6-tri-O-methyl-D-mannose, and 2,3-di-O-methyl-D-mannose in the molar ratio of 1:1.4:0.95. Partial hydrolysis of the galactomannan afforded 4-O-β-D-mannopyranosyl-D-mannose, 6-O-α-D-galactopyranosyl-D-mannose, and two trisaccharides. Based on these results a structural formula for the galactomannan has been proposed, additional evidence for which was adduced from periodate-oxidation studies.

A METHOD FOR THE IDENTIFICATION OF THE MONO-O-METHYLGLUCOSES

1953 ◽  
Vol 31 (9) ◽  
pp. 814-820 ◽  
Author(s):  
R. U. Lemieux ◽  
H. F. Bauer
Keyword(s):  
Paper Chromatography ◽  
Sodium Borohydride ◽  
Alkaline Hydrolysis ◽  
Periodate Oxidation ◽  
Methyl Cellulose ◽  
Water Soluble ◽  
The Other ◽  
Potential Value ◽  
Hydrolysis Of

Periodate oxidation of any one mono-O-methylglucopyranose and alkaline hydrolysis of the product yields a substance which can be positively distinguished by paper chromatography from the products formed under the same conditions from the other mono-O-methylglucopyranoses. Thus, the components of a mixture of the mono-O-methylglucopyranoses can be readily identified. The method appears useful for the identification of di-O-methylglucoses. Reduction with sodium borohydride prior to periodate oxidation renders the method useful for the identification of tri-O-methylglucoses. The potential value of the method, which can be used on a microscale, is illustrated by an application to the characterization of the O-methylglucoses derived from a water-soluble O-methyl-cellulose

Glucan isolated from leaves of Althaea officinalis L.

1983 ◽  
Vol 48 (7) ◽  
pp. 2082-2087 ◽  
Author(s):  
Alžbeta Kardošová ◽  
Jozef Rosík ◽  
Rudolf Toman ◽  
Peter Capek
Keyword(s):  
Medicinal Plant ◽  
Periodate Oxidation ◽  
Linear Structure ◽  
Water Soluble ◽  
Partial Hydrolysis ◽  
Methylation Analysis ◽  
Glycosidic Bonds ◽  
Nmr Data ◽  
Althaea Officinalis ◽  
C Nmr

A water-soluble low-molecular D-glucan was isolated from leaves of the medicinal plant marsh-mallow (Althaea officinalis L.). The results of methylation analysis, partial hydrolysis, periodate oxidation, and 13C NMR data indicated a virtually linear structure with α-(1→6) glycosidic bonds.

THE WATER-SOLUBLE POLYSACCHARIDES OF DERMATOPHYTES: IV. GALACTOMANNANS I FROM TRICHOPHYTON GRANULOSUM, TRICHOPHYTON INTERDIGITALE, MICROSPORUM QUINCKEANUM, TRICHOPHYTON RUBRUM, AND TRICHOPHYTON SCHÖNLEINII

1965 ◽  
Vol 43 (1) ◽  
pp. 30-39 ◽  
Author(s):  
C. T. Bishop ◽  
M. B. Perry ◽  
F. Blank ◽  
F. P. Cooper
Keyword(s):  
Aqueous Solutions ◽  
Copper Complexes ◽  
Trichophyton Rubrum ◽  
Periodate Oxidation ◽  
Structural Features ◽  
Water Soluble ◽  
Major Constituent ◽  
Branch Points ◽  
Terminal Units ◽  
Hydrolysis Of

A group of polysaccharides, called galactomannans I, were precipitated as their insoluble copper complexes from aqueous solutions of the crude polysaccharides obtained from each of the organisms designated in the title. The five galactomannans I were homogeneous under conditions of electrophoresis and ultracentrifugation and had high positive specific rotations. The major constituent monosaccharide was D-mannose; amounts of D-galactose ranged from nil for the polysaccharide from T. rubrum to 13% for that from T. schönleinii. Methylation and hydrolysis of the five galactomannans I yielded varying amounts of the following: 2,3,5,6-tetra-O-methyl-D-galactose (not present in the products from T. rubrum), 2,3,4,6-tetra-O-methyl-D-mannose, 2,3,4-tri-O-methyl-D-mannose, 2,4,6-tri-O-methyl-D-mannose, 3,4-di-O-methyl-D-mannose, and 3,5-di-O-methyl-D-mannose. Periodate oxidation results agreed with the methylation studies. The gross structural features of each galactomannan I appear to be the same, namely, a basic chain of 1 → 6 linked α-D-mannopyranose units for approximately every 22 of which there is a 1 → 3 linked α-D-mannopyranose residue. Branch points occur along the 1 → 6 linked chain at the C2 positions of the D-mannopyranose units and once in every 45 units at the C2 position of a 1 → 6 linked D-mannofuranose residue. The D-galactose in the polysaccharides is present exclusively as non-reducing terminal furanose units; non-reducing terminal units of D-mannopyranose are also present. The variations in the identities and relative amounts of the non-reducing terminal units were the only apparent differences in the gross structural features within this group of polysaccharides.

pH Effects in trypsin catalysis

1969 ◽  
Vol 47 (21) ◽  
pp. 4021-4029 ◽  
Author(s):  
H. P. Kasserra ◽  
K. J. Laidler
Keyword(s):  
Complex Formation ◽  
Ph Dependence ◽  
Specific Rotation ◽  
Ph Effects ◽  
Ph Values ◽  
A Value ◽  
Available Information ◽  
Hydrolysis Of ◽  
Substrate Concentrations ◽  
Covalent Complex

A kinetic study has been made of the trypsin-catalyzed hydrolysis of N-benzoyl-L-alanine methyl ester, at pH values ranging from 6 to 10. The substrate concentrations varied from 1.7 × 10−3 to 4.3 × 10−2 M. From the rates were calculated, at each pH, values of [Formula: see text] (corresponding to [Formula: see text]), [Formula: see text] (corresponding to [Formula: see text]) and [Formula: see text] The specific levorotation of trypsin was measured and found to vary with pH in the pH region 5–11, the change in specific rotation following the ionization of a single group with pK(app) of 9.4. At pH 11 the specific rotation of trypsin, its zymogen, and its phosphorylated derivative were approximately the same, suggesting similar conformations for all three forms of the protein.The kinetic results on the acid side were very similar to those obtained by other investigators for chymotrypsin; they imply that there is a group of [Formula: see text] in the free enzyme, presumably the imidazole function of a histidine residue, and that this group is involved in acylation and deacylation, which can only occur if it is unprotonated. The behavior on the basic side was found to be different from that with chymotrypsin revealing a decrease in [Formula: see text] at high pH corresponding to a value of [Formula: see text] whereas [Formula: see text] showed sigmoid pH-dependence. An interpretation of these results that is consistent with all available information is that a group of [Formula: see text] (presumably the —NH3+ function of the terminal isoleucine) controls the conformation and thereby the activity of the enzyme at different stages of complex formation. In contrast to chymotrypsin, the pK of this ionizing group appears to be generally lowered by covalent complex formation between trypsin and its substrates.

scholarly journals Studies of the polysaccharide fraction from the lipopolysaccharide of Pseudomonas alcaligenes

1974 ◽  
Vol 139 (3) ◽  
pp. 633-643 ◽  
Author(s):  
James A. Lomax ◽  
George W. Gray ◽  
Stephen G. Wilkinson
Keyword(s):  
Gel Filtration ◽  
Periodate Oxidation ◽  
Side Chain ◽  
Partial Hydrolysis ◽  
Methylation Analysis ◽  
Mild Acid Hydrolysis ◽  
Pseudomonas Alcaligenes ◽  
Crude Polysaccharide ◽  
Hydrolysis Of ◽  
Mild Acid

Studies of the lipopolysaccharide of Pseudomonas alcaligenes strain BR 1/2 were extended to the polysaccharide moiety. The crude polysaccharide, obtained by mild acid hydrolysis of the lipopolysaccharide, was fractionated by gel filtration. The major fraction was the phosphorylated polysaccharide, for which the approximate proportions of residues were; glucose (2), rhamnose (0.7), heptose (2–3), galactosamine (1), alanine (1), 3-deoxy-2-octulonic acid (1), phosphorus (5–6). The heptose was l-glycero-d-manno-heptose. The minor fractions from gel filtration contained free 3-deoxy-2-octulonic acid, Pi and PPi. The purified polysaccharide was studied by periodate oxidation, methylation analysis, partial hydrolysis, and dephosphorylation. All the rhamnose and part of the glucose and heptose occur as non-reducing terminal residues. Other glucose residues are 3-substituted, and most heptose residues are esterified with condensed phosphate residues, possibly in the C-4 position. Free heptose and a heptosylglucose were isolated from a partial hydrolysate of the polysaccharide. The location of galactosamine in the polysaccharide was not established, but either the C-3 or C-4 position appears to be substituted and a linkage to alanine was indicated. In its composition, the polysaccharide from Ps. alcaligenes resembles core polysaccharides from other pseudomonads: no possible side-chain polysaccharide was detected.

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