Chromatographic Separation of Sugars with Hydrocellulose

Methylation, periodate oxidation, and partial hydrolysis studies on the capsular polysaccharide, and on the carboxyl reduced polynler, of Klebsiella K21 show the structure to consist of a repeating unit.The anomeric linkages were determined by p.m.r. spectroscopy of isolated oligosaccharides and, in part, by specific enzymes. P.m.r. spectroscopy of the original polysaccharide in methyl sulfoxide-d, showed clearly a ratio of one pyruvic acid ketal (CH,, T 8.5) to five anomeric protons (T 4.65-5.40).Les methodes de methylation, oxydation periodique et hydrolyse partielle portees au polysaccharide capsulaire, et au polyn~ere avec le groupe carboxyle reduit, de Klebsiella K21 ont dCmontre que la structure se compose d'une unite qui se repete.Les liaisons anomeres ont Cte distinguees par la spectroscopie r.m.n. des oligosaccharides isoles et, en partie, par des enzymes specifiques. La spectroscopie i.m.n. du polysaccharide original dans le methyl sulfoxide-d, a etabli le rapport un a cinq entre le cetal de l'acide pyruvique (CH,. r 8.5) et les protons anomeres (t 4.65-5.40). Can. J. Chem.. 51, 198 (1973)

Section: Methylation Analysismentioning

confidence: 99%

The Structure of the Capsular Polysaccharide from Klebsiella K-Type 21

Choy¹,

Dutton²

1973

“…9 Hydrolysis of a portion (10 mg) of the slower moving material gave galactose, arabinose, and threitol in a molar ratio of 2:2:1. Periodate oxidation of the substance (60 mg) gave formaldehyde (1.25 mg) the amount of which indicated a molecular weight of 720.…”

Section: Table I1mentioning

confidence: 99%

Carbohydrates of Centrosema Seed. The Constitution of an Arabino Galactan. I

Unrau¹

1964

Controlled periodate degradatioil (Smith degradation) indicated a complex branched structure with a preponderance of 1,4-glycosidic linkages. Methylation experiinents also indicated a branched structure.The isolation and a few characteristics of a galactan present in Centrosema pluma~i seed have been described in an earlier commuilication (1). Whereas it was previously found that extraction of the crushed seed with hot water yielded an amorphous polysaccharide composed primarily of ~-g a l a c t o~e (927,) with lesser amounts of arabinose and mannose, the sample of seed used in this investigation gave a product which contained galactose and arabinose, but no mannose could be detected. I t was therefore suspected that two or more related polysaccharides were present in the seed.The use of complexing agents in the fractionation of polysaccharide mixtures has met with considerable success ( 2 ) . Probably all galactoinannans obtained from legunlinous seeds form copper complexes. Neutral copper sulphate solutions, which contain the cation Cu(OH2)4++ (3), precipitate yeast lnannan and the Lupinus albus galactan. Alkaline copper sulphate solution, containing the anion Cu(0H)d--(3), precipitates a greater range of gums and mucilages. I t is believed that the same structural characteristics are required in the formation of polysaccharide copper complexes as are necessary for borate complex formation, namely, adjacent cis hydroxyls. In the case of the borate anion, B(OH)dd, it is believed that cross linkages are formed between two adjacent polymeric chains resulting in a three dimensional network (4, 5). The arabinogalactan with which this cornmunicatio~l is concerned showed little or no evidence of forming a borate complex. Treatment oi an aqueous solution with Fehling's solution gave a rigid gel. I t was found that 8070 of the original starting material formed a copper complex. Acid hydrolysis of this polysaccharide showed it to be composed of D-galactose (92.5%) and L-arabinose (7y0). Results obtained froin partial hydrolysis of the arabinogalactan showed that the greater proportion (SOY0) of arabinose units were released. This indicated that the arabinose residues were mainly present as nonreducing terminal furanosyl units, a structural feature which has been observed in a fairly large number of polysaccharides containing this pentose (2). A series of internal arabinofuranosyl units could also explain this result although such a structure is less likelyThe further investigation of the structure of the polysaccharide using the Smith degradation (6) largely confirmed the earlier findings ( I ) , although some interior structural systems were found t o be much more complex than \\;as a t first believed. The absence of

“…The neutral sugar glycosides were hydrolyzed and resolved on a cellulose-hydrocellulose coluinn (6) with the sirupy colnpound isolated by Geerdes and Sinith from methylated flax heinicellulose (7). Since the disaccharide D-xylose-P(1 -+ 4)-D-xylose is well known and has a negative rotation (8) it lnay be assulned that its methylated derivative would also be negative.…”

mentioning

confidence: 99%

The Constitution of the Hemicellulose of Apple Wood (Malus Pumila L. Var. Golden Transparent)

Dutton¹,

Murata²

1961

The hemicell~~lose isolated by direct alkaline extraction of the wood has been shown to be a 4-0-mcthylglucuronoxylan. R~Iethylation data indicate a backbone of approxi~nately 120 D-xylopyranose units linked by P,1-4 bonds with single units of 4-0-methyl-D-glucuronic acid linked by or, 1-2 bonds.proportion of acid units to xylose is approximately 1:6. Two artifacts were isolated from the hydrolysis products of the methylated polysaccharide:4-0-(2,3-di-0-methyl-or-~-xylopyranosyl)-2,-d1--meth-~-xyose and 2,3-di-0-methyl-D-lyxose.I-Ieinicelluloses froin many deciduous and coniferous trees have been isolated and studied, and these results have been reviewed (1). The majority of the trees so far investigated have been those of conllnercial importance for pulping, such as birch, beech, hemlock, and spruce, etc. Certain generalizations on the structure of he~nicellu-loses have emerged as a result of these studies, the most notable being that the he~ni-celluloses from coniferous trees have a high mannosk content whereas those from deciduous trees are very low in this sugar (1). I t was of interest t o include other species in these structural investigations and accordingly the hemicelluloses from two ~nembers of the Rosaceae family have been studied. The present paper reports the results on ~VIalus m i a i l l . (var. Golden Transparent), and the results on Prz~nz~s avium L. (var. Bing) will be reported later (2).Finely ground apple wood was extracted with hot alco11ol:benzene (1:2) and the air-dried residue was shaken with 0.1 N sodium hydroxide.highly colored extract was discarded and the residue re-extracted with 1 N sodium hydroxide according to the method of l/lcDonald (3). The hemicellulose was isolated by pouring the alk* CL 1' ine extract into acidified ethanol and, after being dried by solvent exchange, amounted to 8-12y0 of the dry wood.The hydrolysis products of the hemicellulose were resolved on ion exchange resins into a neutral and an acidic fraction. Chromatographic analysis of the former showed it to contain predominantly D -X Y~O S~ which was characterized as the crystalline sugar. There were also trace amounts of arabinose, galactose, and rhamnose, together with two components having a greater mobility than rhainnose. The identities of these two sugars have not yet been determined. The acidic fraction contained appreciable amounts of an aldobiouronic acid, characterized by conversion t o the crystalline methyl 2-0-(2,3-di-0-acetyl-4-0-i~1et~1yl-cr-~-glucopyranosy)ro~te 3,4-di-0-acetyl-D-xylopyranoside (4), together with smaller amounts of nlaterials assumed t o be free uronic acid and an aldotriouronic acid.The hemicellulose was methylated, fractionated, and cleaved by methanolysis. After the methyl esters of the acidic conlponents had been saponified with bariuin hydroxide the mixture of glycosides was resolved into neutral and acidic portions. The acidic fraction was re-esterified with diazoinethane and reduced with lithium aluminum hydride with the expectation that the crystalline methyl 2-...