THE STRUCTURE OF LINSEED MUCILAGE: PART II

1962 ◽  
Vol 40 (7) ◽  
pp. 1266-1279 ◽  
Author(s):  
K. Hunt ◽  
J. K. N. Jones

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.

1964 ◽  
Vol 42 (1) ◽  
pp. 107-112 ◽  
Author(s):  
A. K. Bhattacharyya ◽  
C. V. N. Rao

Gum Jeol has been shown to be composed of residues of D-galactose, L-arabinose, and D-galacturonic acid. On mild acid hydrolysis the gum gave an aldobiouronic acid, viz. 3-O-(D-galactopyranosyl uronic acid)-D-galactopyranose. Hydrolysis of the fully methylated degraded gum yielded 2,3,4,6-terra-(3 moles); 2,3,4-tri-(2 moles); 2,4-di-(1 mole); and 2-O-methyl-D-galactose (1 mole) in the neutral fraction of the hydrolyzate. The reduced acidic fraction yielded 2,3,4-tri-(2 moles) and 2,4-di-O-methyl-D-galactose (2 moles). Based on these results a partial structure of the degraded gum has been proposed, the additional evidence of which was deduced from periodate oxidation studies of the degraded gum.


2016 ◽  
Vol 64 (1) ◽  
pp. 83-88
Author(s):  
Nilufar Nahar ◽  
AKM Ahsan Habib ◽  
SM Mizanur Rahman ◽  
Tofail Ahmed Chowdhury

Arabinogalactan and rhamnogalactglucuronan were isolated from soluble dietary fiber (SDF) of cauliflower. The isolated SDF was fractioned into neutral and acidic parts by ion-exchange column chromatography using DEAESepharose Cl-6B gel. Structure elucidation of the isolated SDF polysaccharides were determined sugar analysis, 1HNMR, H-H COSY and TOCSY spectroscopic studies. Neutral fraction of cauliflower was found to be composed of galactose, arabinose and rhamnose whereas the acidic part was found to contain rhamnose, galactose, galacturonic and glucuronic acids. The main chain of the neutral fraction was found to be a 1,4-?-galactan where terminal rhamnose and arabinose residues were attached to the main chain at the 3-position of by ?-linkage.The main chain of the acidic fraction was composed of 1,4-b-linked galacturonic acid and 1,2-b-linked rhamnopyranose residues. ?- Glucuronic acid and ?-galactose were attached to the main chain of galacturonic acid at its 3-position.Dhaka Univ. J. Sci. 64(1): 83-88, 2016 (January)


1966 ◽  
Vol 44 (11) ◽  
pp. 1275-1282 ◽  
Author(s):  
V. Zitko ◽  
C. T. Bishop

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.


1961 ◽  
Vol 39 (4) ◽  
pp. 889-896 ◽  
Author(s):  
P. Kooiman ◽  
G. A. Adams

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.


1969 ◽  
Vol 47 (15) ◽  
pp. 2883-2887 ◽  
Author(s):  
V. P. Kapoor ◽  
S. Mukherjee

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.


1965 ◽  
Vol 43 (1) ◽  
pp. 30-39 ◽  
Author(s):  
C. T. Bishop ◽  
M. B. Perry ◽  
F. Blank ◽  
F. P. Cooper

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.


1962 ◽  
Vol 40 (12) ◽  
pp. 2204-2213 ◽  
Author(s):  
A. Misaki ◽  
S. Kirkwood ◽  
J. V. Scaletti ◽  
F. Smith

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.


1989 ◽  
Vol 258 (1) ◽  
pp. 23-32 ◽  
Author(s):  
I H Batty ◽  
A J Letcher ◽  
S R Nahorski

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.


1990 ◽  
Vol 68 (1) ◽  
pp. 44-53 ◽  
Author(s):  
Antti Seppo ◽  
Leena Penttilä ◽  
Anne Makkonen ◽  
Anne Leppänen ◽  
Ritva Niemelä ◽  
...  

GlcNAcβ1-3(GlcNAcβ1-6)[14C(U)]Gal and GlcNAcβ1-3(GlcNAcβ1-6)[14C(U)]Galβ1-4GlcNAc were prepared by in vitro synthesis. They were characterized by enzymatic sequencing, by partial acid hydrolysis, and by periodate oxidation experiments. The two saccharides were isolated also from partial acid hydrolysates of metabolically labeled poly-N- acetyllactosaminoglycans of murine embryonal carcinoma cells (line PC 13). The tetrasaccharide was retarded in a column of agarose-linked wheat germ agglutinin; the trisaccharide was strongly bound. Chromatography in this column separated the trisaccharide into two distinct peaks, which represented interconvertible molecules. Together with our previous data on linear teratocarcinoma saccharides, these findings show that affinity chromatography with immobilized wheat germ agglutinin can be advantageously used in fractionating radiolabeled oligo-N-acetyllactosaminoglycans and saccharides related to them.Key words: GlcNAcβ1-3(GlcNAcβ1-6)Gal, GlcNAcβ1-3(GlcNAcβ1-6)Galβ1-4GlcNAc, wheat germ agglutinin – agarose chromatography, in vitro biosynthesis, teratocarcinoma cell.


1971 ◽  
Vol 125 (2) ◽  
pp. 473-480 ◽  
Author(s):  
M. A. Obaidah ◽  
K. W. Buck

1. The nature of two polysaccharides (s020 values 6S and 2S respectively in 1m-sodium hydroxide), comprising a fragment (fraction BB, [α]D +236° in 1m-sodium hydroxide), previously isolated from cell walls of Fusicoccum amygdali, has been investigated. 2. Both the major (2S) and minor (6S) components were affected by incubation with α-amylase. The 6S polysaccharide was also attacked by exo-β-(1→3)-glucanase, which is evidence that it contained both α-(1→4)- and β-(1→3)-glucopyranose linkages. By fractionation of the products of α-amylase-treated fraction BB it was possible to obtain a water-insoluble polysaccharide, fraction P ([α]D +290° in 1m-sodium hydroxide, 67% of fraction BB) and a water-soluble polysaccharide, fraction Q ([α]D +16° in 1m-sodium hydroxide, 11% of fraction BB), both of which sedimented as single boundaries with s020 values (in 1m-sodium hydroxide) of 1.7S and 4.6S respectively. 3. Evidence from periodate oxidation, methylation analysis, i.r. spectroscopy and partial acid hydrolysis showed that fraction P consisted of linear chains of α-(1→3)-glucopyranose units with blocks of one or two α-(1→4)-glucopyranose units interspersed at intervals along the main chain. The 2S polysaccharide, from which fraction P is derived, evidently also contains longer blocks of α-(1→4)-glucopyranose units, that are susceptible to α-amylase action. 4. Fraction Q consisted of glucose (88%) with small amounts of galactose, mannose and rhamnose. Evidence from digestion with exo- and endo-β-(1→3)-glucanases, periodate oxidation and methylation analysis suggests that fraction Q consists of a branched galactomannorhamnan core, to which is attached a β-(1→3)-, β-(1→6)-glucan. In the cell wall, chains of α-(1→4)-linked glucopyranose units are linked to fraction Q to form the 6S component of fraction BB.


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