Carbohydrate Esters Research Articles

Spectrophotometric determination of phosphate esters in the presence and absence of orthophosphate

A simple modified molybdovanadate method for the simultaneous assay of orthophosphate and some organic phosphates, especially carbohydrate esters, is described. The method is applicable to the study of specificity of phosphatases and assay of individual esters after chromatographic separation.

Acyl migrations in acylated monosaccharides. Formation of N-acetyl-β- D-galactofuranosylamine

The conformational and steric factors that determine the different contributions of the acyl groups to the formation of 1,1-bis(acylamido)-1-deoxyalditols by the ammonolysis of acyl esters of carbohydrates of different structures are discussed. The isolation and structure of N-acetyl β- D-galactofuranosylamine, obtained by such a reaction, are reported, and the conformation of this sugar and that of the N-acetyl-α- D-glucofuranosylamine previously described are considered on the basis of n.m.r. data.

Determination of sulphate and of barium in carbohydrate sulphates by flame photometry

Methods are described for the determination of barium and of sulphate in carbohydrates by using an EEL flame photometer. The intensity of the barium flame is unaffected by the presence of carbohydrates, and the barium content is determined by direct examination of a solution of the carbohydrate. Prior to sulphate assay, the carbohydrate ester is heated with nitric acid; hydrolysis with hydrochloric acid is unsatisfactory in some cases. The sulphate is then determined by precipitation as barium sulphate, followed by dissolution of the latter in ethylenediamine tetra-acetate solution and photometric assay. An alternative, more-direct method, in which the concentration of barium remaining after introduction of sulphate and centrifugation is measured, is less accurate. The methods have been successfully applied to a range of sugar and polysaccharide sulphates with 2–5 mg samples.

Selective reactions of sulfonic esters of carbohydrates on alumina

Selective reactions of sulfonic esters of carbohydrates on alumina

Sulfonic Esters of Carbohydrates: Part I

This chapter discusses the sulfonic esters of carbohydrates. Adequate methods for sulfonylation existed, and an introduced sulfonyl group provided a protecting group stable under acidic, neutral, and slightly basic conditions. Removal of the sulfonyl protecting group is known to be readily achieved by the use of sodium amalgam. The action of alkaline reagents on sulfonic esters received much attention, and the nature of the products from derivatives containing isolated or nonisolated, primary or secondary sulfonyloxy groups are known. The use of Finkelstein's reagent with sulfonic esters of sugars provided another reaction of considerable utility; the resulting replacement of primary and secondary sulfonyloxy groups with iodine in a variety of sugars is reviewed. Nucleophilic displacements of sulfonyloxy groups by reagents other than halide ions are also observed in sugar chemistry. Much of the stimulus for work on sulfonic esters of sugars has arisen from their use in the synthesis of compounds having possible chemotherapeutic activity.

Conversion of Equatorial Mesyl Esters of Carbohydrates to Ethers with Retention of Configuration by Reaction with Alkoxides in Dimethyl Sulfoxide1

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTConversion of Equatorial Mesyl Esters of Carbohydrates to Ethers with Retention of Configuration by Reaction with Alkoxides in Dimethyl Sulfoxide1E. D. M. Eades, D. H. Ball, and L. Long Jr.Cite this: J. Org. Chem. 1966, 31, 4, 1159–1162Publication Date (Print):April 1, 1966Publication History Published online1 May 2002Published inissue 1 April 1966https://doi.org/10.1021/jo01342a041RIGHTS & PERMISSIONSArticle Views85Altmetric-Citations11LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (627 KB) Get e-Alerts Get e-Alerts

INFLUENCE OF INGESTED CASEIN HYDROLYZATE ON THE HIGH ENERGY NUCLEOTIDE CONTENT OF WORKING MUSCLE

The results of experiments carried out on albino rats show that administration, during periods of continued muscular activity, of casein hydrolyzate, a mixture of amino acids, or phosphoric acid salts, favors the maintenance of a higher than normal level of adenosine triphosphate (ATP) and phosphocreatine (CP) and a corresponding decrease in the level of adenosine diphosphate (ADP) and adenosine monophosphate (AMP) in the muscles.It appears from this study that just as carbohydrate is known to have a protein-sparing action, so amino acids have been found to have a sparing action in the metabolism of carbohydrate and phosphate ester in the animal even under conditions of intense physical exercise at low temperatures.

INFLUENCE OF INGESTED CASEIN HYDROLYZATE ON THE HIGH ENERGY NUCLEOTIDE CONTENT OF WORKING MUSCLE

The results of experiments carried out on albino rats show that administration, during periods of continued muscular activity, of casein hydrolyzate, a mixture of amino acids, or phosphoric acid salts, favors the maintenance of a higher than normal level of adenosine triphosphate (ATP) and phosphocreatine (CP) and a corresponding decrease in the level of adenosine diphosphate (ADP) and adenosine monophosphate (AMP) in the muscles.It appears from this study that just as carbohydrate is known to have a protein-sparing action, so amino acids have been found to have a sparing action in the metabolism of carbohydrate and phosphate ester in the animal even under conditions of intense physical exercise at low temperatures.

SOMITE GENESIS IN THE CHICK. II. ANALYSIS OF NUTRIENTS FROM YOLK

1. Definitive primitive streak chick embryos have been cultured in vitro on media containing various fractions of whole yolk. Other embryos were grown on agar gels containing fractions derived by barium and alcohol fractionation of yolk and albumen dialysates. Following 22 hours of incubation, the blastoderms were mounted and examined for the development of somites.2. The nutritional components of whole yolk are all present in the saline-soluble, dialyzable moiety, although the embryo can use the acid hydrolysate of dialyzed yolk, when accompanied by glucose, for this morphogenetic process.3. The results, derived from an assay of barium and alcohol fractionation of both yolk and egg white, indicate that the early chick embryo can use, to limited extent, certain phosphate esters of carbohydrates in the formation of somites. There appear to be different phosphorylated materials in yolk than in albumen used by the embryo.4. Insofar as whole yolk utilization is concerned for the formation of somites, there is evidence that the chick embryo grown in vitro uses: (1) glucose, (2) the amino acids found free in yolk, (3) a heat-labile, uncharacterized factor, and (4) certain phosphorylated carbohydrate intermediates. It may also use, but to a very limited extent, the products of proteolysis of yolk proteins.

The Location of Metaphosphate in the Yeast Cell

All metachromatically staining substances were originally thought by Lison (1935a; 1935b) to be the sulfuric esters of high-polymeric carbohydrates. Michaelis (1947) found that high-polymeric carbohydrates with carboxyl groups such as the capsular substances of pneumococci and mucin stain metachromatically (purple to red) with toluidine blue. Wiame (1946) found that metaphosphate also stains metachromatically. Both Wiame and Michaelis have shown by spectrophotometric analyses that metachromasy (when toluidine blue is used as the stain) is dependent upon (1) the concentration of metaphosphate, (2) the concentration of dye, and (3) the condition of the metaphosphate.The following tests devised by Grimme (1902) for the detection of volutin (metaphosphate), have been retained in general use: 1) metachromatic staining with dilute methylene blue, 2) extractability from unfixed cells with hot water at 80°C in five minutes, and 3) retention of the stain after treatment with 1 per cent sulfuric acid. Acid fastness is superior to the occurrence of metachromasy as a test for the presence of volutin.A cytological investigation of the location of metaphosphate (volutin) in the yeast cell was made in two types of preparations: 1) fixed impression smears and 2) progressively stained living cells. Essentially the same results were obtaned with both preparations except that the vacuoles were destroyed by drying the impression smears. The results showed that volutin (metaphosphate) is confined to the nuclear vacuole.There are three items which have led to erroneous conclusions concering the location of metaphosphate. The spindle, which is not visible in the unstained cell, often appears after staining as a clear area and is mistaken for the vacuole. Heavy deposits of glycogen similarly appear in the stained cell as clear areas and have been mistaken for the vacuole. The mitochondria, which are obvious in the cytoplasm, are destroyed by the staining and have been confused with the chromosomes covered with volutin which appear after staining.

Biological Properties and Chemical Synthesis of Phosphoric Esters of Carbohydrates

Biological Properties and Chemical Synthesis of Phosphoric Esters of Carbohydrates

Sulfonic Esters of Carbohydrates

Publisher Summary This chapter discusses sulfonic esters of carbohydrates. Of the various ways in which sulfonic esters may be synthesized, only two––the use of metallic salts of sulfonic acids and the use of suljonyl halides–– have so far achieved importance in carbohydrate chemistry. Certain sulfonic esters of sugars and sugar alcohols may be employed for hydroxyalkylation. In purifying, and assessing the purity of, sulfonic esters of sugars, knowledge of some of their general physical properties is helpful. Many sulfonic esters of monosaccharides and their derivatives crystallize with comparative ease, thereby affording a means of purification. A few sulfonic esters of sugars have been purified chromatographically. Crystalline sulfonic esters of monosaccharides and their derivatives are colorless, and exhibit sharp melting points. Sulfonic esters of sugar alcohols often react similarly with ammonia; thus, 1,4:3,6-dianhydro-2,5-di-O-tosyl-D-manniatnold -sorbitol give the corresponding 2,5-diamino-2,5-dideoxy derivatives.

Methacrylic Esters of Glucose and Other Carbohydrates1

Methacrylic Esters of Glucose and Other Carbohydrates¹