scholarly journals CONSTITUTION OF A GLUCOMANNAN FROM TAMARACK (LARIX LARICINA)

1961 ◽  
Vol 39 (4) ◽  
pp. 889-896 ◽  
Author(s):  
P. Kooiman ◽  
G. A. Adams
Keyword(s):  
Free Boundary ◽  
Main Chain ◽  
Periodate Oxidation ◽  
Larix Laricina ◽  
Hydrolysis Of

A hemicellulose fraction containing D-mannose, D-glucose, and D-galactose in a ratio of 70:25:3 has been isolated from tamarack wood. The product was homogeneous under conditions of free boundary electrophoresis and of sedimentation in the ultracentrifuge. Hydrolysis of the fully methylated hemicellulose yielded 2,3,4,6-tetra-O-methyl-D-glucose (1.2%); 2,3,4,6-tetra-O-methyl-D-galactose (2.2%); 2,3,6-tri-O-methyl-D-glucose (24.0%); 2,3,6-tri-O-methyl-D-mannose (68.8%); 2,3-di-O-methyl-D-mannose (1.6%); and 2,3-di-O-methyl-D-glucose (1.7%). This data and that from periodate oxidation indicated that the glucomannan had a linear backbone of approximately 35 (1 → 4) linked β-D-glucopyranose and β-D-mannopyranose units; approximately two thirds of the chains were terminated at the non-reducing ends by D-galactose and the remainder by D-glucose. Branching, if present, must occur through C6 of the hexoses in the main chain.

THE STRUCTURE OF LINSEED MUCILAGE: PART II

1962 ◽  
Vol 40 (7) ◽  
pp. 1266-1279 ◽  
Author(s):  
K. Hunt ◽  
J. K. N. Jones
Keyword(s):  
Galacturonic Acid ◽  
Main Chain ◽  
Periodate Oxidation ◽  
Neutral Fraction ◽  
Acetate Solution ◽  
Partial Acid Hydrolysis ◽  
Cupric Acetate ◽  
Acidic Fraction ◽  
Degraded Material ◽  
Hydrolysis Of

Linseed mucilage has been separated into an acidic and a neutral fraction. The acidic fraction was further separated, by the use of cupric acetate solution, into two fractions, CuI and CuII. Fraction CuI contained L-rhamnose, L-galactose, and D-galacturonic acid. The methylated reduced polysaccharide gave on hydrolysis 2,3,4-tri-O-methyl-L-rhamnose, 3,4-di-O-methyl-L-rhamnose, 4-O-methyl-L-rhamnose, 2,3,4,6-tetra-O-methyl-D-galactose, 2,3,6-tri-O-methyl-D-galactose, and 2,3-di-O-methyl-D-galactose (?); L-galactose was lost during the methylation process. Periodate oxidation studies on the material indicated that the polymer was composed of a main chain of L-rhamnose units with most of the L-galactose units attached as non-reducing end groups. Fraction CuII contained L-rhamnose, L-fucose, L-galactose, and D-galacturonic acid. The methylated reduced polysaccharide gave on hydrolysis 2,3,4-tri-O-methyl-L-fucose, 2,3,4,6-tetra-O-methyl-L-galactose, 2,3,6-tri-O-methyl-D-galactose, 4-O-methyl-L-rhamnose, L-rhamnose, and possibly 2,3-di-O-methyl-D-galactose and 3-O-methyl-D-galactose. Periodate oxidation studies and a degradation by the Smith procedure indicated the presence of a L-rhamnose backbone with L-fucose and L-galactose units attached as non-reducing end groups.The neutral fraction yielded a periodate-oxidizable material after one Smith-type degradation. Periodate oxidation studies indicated that the degraded material was branched. Methylation of the degraded polysaccharide followed by hydrolysis yielded 2,3,4-tri-O-methyl-D-xylose, 2,3-di-O-methyl-D-xylose, 2,4-di-O-methyl-D-xylose, 4-O-methyl-D-xylose, D-xylose, and traces of 2,3,4-trt-O-methyl- or 2,5-di-O-methyl-L-arabinose, 2,4-di-O-methyl-D-xylose, and 3-O-methyl-D-xylose. The main backbone of the degraded polysaccharide appeared to consist of (1 → 4)-linked D-xylose units. Linkages of the (1 → 3) type were also present. The smaller fragments from the Smith-type degradation, L-arabinose, 2-O-α-L-arabinosyl glycerol, and glycerol were characterized. A partial acid hydrolysis of the neutral fraction yielded a number of oligosaccharides.

Galactomannan from Cassiaabsus seed. I. Nature of sugars present, methylation, and periodate oxidation studies

1969 ◽  
Vol 47 (15) ◽  
pp. 2883-2887 ◽  
Author(s):  
V. P. Kapoor ◽  
S. Mukherjee
Keyword(s):  
Formic Acid ◽  
Main Chain ◽  
Periodate Oxidation ◽  
Branch Points ◽  
Ca 50 ◽  
Hydrolysis Of

A galactomannan composed of D-galactose (1 mole) and D-mannose (3 moles) was isolated from the seed of Cassiaabsus. Methylation and hydrolysis of the galactomannan produced 2,3,4,6-tetra-O-methyl-D-galactose (2 moles), 2,3,6-tri-O-methyl-D-mannose (4.2 moles), 2,3-di-O-methyl-D-mannose (1 mole), and 4,6-di-O-methyl-D-mannose (1 mole). Periodate consumption was 1.09 moles for each hexose unit with concomitant liberation of 0.26 mole of formic acid. The periodate oxidized and the reduced galactomannan afforded, on hydrolysis, glycerol (1.94 moles), erythritol (5 moles), and D-mannose (1.08 moles).On the basis of the above findings, a structure for the galactomannan can be proposed in which mannose units form the main chain and the galactose units are present as branches, the former being attached mostly through 1 → 4 (ca. 85%) and the rest which is nearly half the branch points through 1 → 3 or 1 → 2, and branches of single galactose units are attached through 1 → 6 (ca. 50%) and the rest through 1 → 2 or 1 → 3.

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.

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.

STRUCTURE OF A GALACTURONAN FROM SUNFLOWER PECTIC ACID

1966 ◽  
Vol 44 (11) ◽  
pp. 1275-1282 ◽  
Author(s):  
V. Zitko ◽  
C. T. Bishop
Keyword(s):  
Galacturonic Acid ◽  
Periodate Oxidation ◽  
Degree Of Polymerization ◽  
Critical Assessment ◽  
Molar Ratio ◽  
Aqueous Methanol ◽  
Pectic Acid ◽  
Potassium Borohydride ◽  
Rate Of Hydrolysis ◽  
Hydrolysis Of

Fractions of sunflower pectic acid containing 89.8%, 94.2%, and 91.4% of D-galacturonic acid were carboxyl reduced as their methyl or ethylene glycol esters by potassium borohydride. Critical assessment of the effects of three different solvents (water, 80% aqueous dimethyl sulfoxide, and 80% aqueous methanol) on the efficiency of reduction showed that the latter solvent was best. The reductions caused a decrease in the degree of polymerization from 270 to 21. Measurement of the rates of hydrolysis of partially reduced pectic acids containing 90%, 41.6%, 19.9%, 11.0%, and 0.65% of D-galacturonic acid showed that the rate of hydrolysis was directly related to the proportion of galacturonosidic linkages present. Methylation and hydrolysis of the carboxyl-reduced pectic acid fractions yielded 2,3,4,6-tetra-O-methyl-D-galactose and 2,3,6-tri-O-methyl-D-galactose in an approximate molar ratio of 1:20. Results of the periodate oxidation of the carboxyl-reduced pectic acid supported the conclusion inferred from the methylation results that the pectic acid was a linear polymer of 1 → 4 linked α-D-galacturonic acid units.

scholarly journals Accumulation of inositol polyphosphate isomers in agonist-stimulated cerebral-cortex slices. Comparison with metabolic profiles in cell-free preparations

1989 ◽  
Vol 258 (1) ◽  
pp. 23-32 ◽  
Author(s):  
I H Batty ◽  
A J Letcher ◽  
S R Nahorski
Keyword(s):  
Cerebral Cortex ◽  
Inositol Phosphates ◽  
Periodate Oxidation ◽  
Chemical Degradation ◽  
Inositol Polyphosphate ◽  
Tissue Slices ◽  
Inositol 1 ◽  
Agonist Stimulation ◽  
Cortex Slices ◽  
Hydrolysis Of

1. Basal and carbachol-stimulated accumulations of isomeric [3H]inositol mono-, bis-, tris- and tetrakis-phosphates were examined in rat cerebral-cortex slices labelled with myo-[2-3H]inositol. 2. In control samples the major [3H]inositol phosphates detected were co-eluted on h.p.l.c. with Ins(1)P, Ins(4)P (inositol 1- and 4-monophosphate respectively), Ins(1,4)P2 (inositol 1,4-bisphosphate), Ins(1,4,5)P3 (inositol 1,4,5-tris-phosphate) and Ins(1,3,4,5)P4 (inositol 1,3,4,5-tetrakisphosphate). 3. After stimulation to steady state with carbachol, accumulation of each of these products was markedly increased. 4. Agonist stimulation, however, also evoked much more dramatic increased accumulations of a second [3H]inositol trisphosphate, which was co-eluted on h.p.l.c. with authentic Ins(1,3,4)P3 (inositol 1,3,4-trisphosphate) and of three further [3H]inositol bisphosphates ([3H]InsP2(s]. 5. Examination of the latter by chemical degradation by periodate oxidation and/or h.p.l.c. allowed identification of these as [3H]Ins(1,3)P2, [3H]Ins(3,4)P2 and [3H]Ins(4,5)P2 (inositol 1,3-, 3,4- and 4,5-bisphosphates respectively), which respectively accounted for about 22%, 8% and 3% of total [3H]InsP2 in extracts from stimulated tissue slices. 6. By using a h.p.l.c. method which clearly resolves Ins(1,3,4,5)P4 and Ins(1,3,4,6)P4 (inositol 1,3,4,6-tetrakisphosphate), only the former isomer could be detected in extracts from either control or stimulated tissue slices. Similarly, [3H]inositol pentakis- and hexakis-phosphates were not detectable either in the presence or absence of carbachol under the radiolabelling conditions described. 7. The catabolism of [3H]Ins(1,4,5)P3 and [3H]Ins(1,3,4)P3 by cell-free preparations from cerebral cortex was also studied. 8. In the presence of Mg2+, [3H]Ins(1,4,5)P3 was specifically dephosphorylated via [3H]Ins(1,4)P2 and [3H]Ins(4)P to free [3H]inositol, whereas [3H]Ins(1,3,4)P3 was degraded via [3H]Ins(3,4)P2 and, to a lesser extent, via [3H]Ins(1,3)P2 to D- and/or L-[3H]Ins(1)P and [3H]inositol. 9. In the presence of EDTA, hydrolysis of [3H]Ins(1,4,5)P3 was greater than or equal to 95% inhibited, whereas [3H]Ins(1,3,4)P3 was still degraded, but yielded only a single [3H]InsP2 identified as [3H]Ins(1,3)P2. 10. The significance of these observations with cell-free preparations is discussed in relation to the proportions of the separate isomeric [3H]inositol phosphates measured in stimulated tissue slices.

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.

Network Scission Processes in Peroxide Cured Methylvinyl Silicone Rubber

1967 ◽  
Vol 40 (2) ◽  
pp. 629-634
Author(s):  
D. K. Thomas
Keyword(s):  
Silicone Rubber ◽  
Elevated Temperatures ◽  
Main Chain ◽  
Methyl Groups ◽  
Chain Polymer ◽  
Filled Rubber ◽  
Oxidative Reactions ◽  
Silica Filler ◽  
Silicone Rubbers ◽  
Hydrolysis Of

Abstract In what appeared to be a complex system it transpires that network scission in methylvinyl silicone rubbers at temperatures below 250° C is due largely to hydrolytic reactions in the main chain polymer. At temperatures of 250° C and above there are indications that a significant amount of scission arises from oxidative reactions in the crosslinks, and that this reaction is catalyzed by acidic residues in the rubber. There is no indication that acidic byproducts of the vulcanization reaction catalyze the hydrolysis of siloxane bonds in the polymer. In conventional heat aging tests in which the rubber remains in an unstrained condition the effects of hydrolysis will only be observed if the concentration of water in the system is allowed to rise. Under these circumstances softening will occur because of a shift in the position of equilibrium in the reaction ∼Si—O—Si—O∼ + H2O→∼Si—OH+ HO—Si—O∼ On aging the material in a well ventilated situation the effects of hydrolysis are not seen and the silicone rubber becomes brittle after long exposure at high temperature. This embrittlement must result from additional crosslinking caused by oxidative reactions in the methyl groups of the main chain polymer. When the rubber is used in compression or tension, hydrolytic scission will affect performance, and in applications of this sort it is important to dry the rubber before use and prevent access of moisture to the component during use. With filled rubber the silica filler is a further source of moisture and drying needs to be carried out at elevated temperatures immediately before use. In order to improve the confined heat aging performance of silicone rubber an alternative filler to fine silica is needed which does not have the same affinity for water. It may be, however, that ability to reinforce silicone rubber and affinity for water are inseparable.

scholarly journals IMMUNOCHEMICAL STUDIES ON BLOOD GROUPS

1971 ◽  
Vol 133 (1) ◽  
pp. 39-52 ◽  
Author(s):  
Ten Feizi ◽  
Elvin A. Kabat ◽  
Giuseppe Vicari ◽  
Byron Anderson ◽  
W. Laurence Marsh
Keyword(s):  
Acid Hydrolysis ◽  
Blood Group ◽  
Ovarian Cyst ◽  
Periodate Oxidation ◽  
Human Saliva ◽  
Mild Acid Hydrolysis ◽  
Group B ◽  
Hydrolysis Of ◽  
Substantial Heterogeneity ◽  
Mild Acid

A partially purified blood group-like substance obtained from milk showed I activity with 2 of 21 anti-I sera. With these antisera, certain human ovarian cyst substances considered to be precursors of the A, B, H, Lea, and Leb substances also showed I activity comparable to the milk material. Strong I activity could be produced by one-stage periodate oxidation and Smith degradation of human ovarian cyst A and B substances, or of hog mucin A + H substance, or by mild acid hydrolysis of human saliva or ovarian cyst blood group B substance. The two sera indicate that I specificity appears at intermediate stages in the biosynthesis of the A, B, H, Lea, and Lea substances. Anti-I sera differ strikingly in their specificities, indicating substantial heterogeneity of the I determinants.

CONSTITUTION OF A DEGRADED POLYSACCHARIDE FROM WHEAT BRAN

1957 ◽  
Vol 35 (2) ◽  
pp. 108-114 ◽  
Author(s):  
J. Schmorak ◽  
C. T. Bishop ◽  
G. A. Adams
Keyword(s):  
Acid Hydrolysis ◽  
Wheat Bran ◽  
Glucuronic Acid ◽  
Periodate Oxidation ◽  
Glycosidic Bond ◽  
Cellulolytic Enzyme ◽  
Acidic Polysaccharide ◽  
Hydrolysis Of ◽  
End Group ◽  
Acid Unit

Graded acid hydrolysis of a soluble wheat bran hemicellulose containing L-arabinose (50%), D-xylose (38.5%), and D-glucuronic acid (9.0%) preferentially removed the L-arabinose giving an insoluble acidic polysaccharide in approximately 25% yield by weight. Methylation studies, periodate oxidation data, and hypoiodite end group estimations showed that the degraded polysaccharide was composed of repeating units of 7-8 D-xylopyranose residues joined by β,1 → 4 linkages. To this repeating unit, one D-glucuronic acid unit was attached by a 1 → 2 glycosidic bond. The cellulolytic enzyme of Myrotheciumverrucaria, which is specific for β,1 → 4 glycosidic linkages, hydrolyzed the degraded polysaccharide although it had no effect on the parent hemicellulose

Sign in / Sign up

Export Citation Format

Share Document