uronic acid

[yə′rän·ik ′as·əd]

(organic chemistry)

One of the compounds that are similar to sugars, except that the terminal carbon has been oxidized from the alcohol to a carboxyl group; for example, galacturonic acid and glucuronic acid.

The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

Uronic Acid

any of the organic substances that are related to monosaccharides but that are distinguished from the latter by having a carboxyl group (—COOH) in place of the—CH₂OH radical. The difference is illustrated by the following structural formulas:

Uronic acids are crystalline or amorphous substances that are nonvolatile, relatively high-melting, and readily soluble in water and polar solvents. Chemically, they possess the properties of both monosaccharides (mutarotation, oxidation, reduction, ability to form glycosides) and hydroxy acids (formulation of esters and lactones). Uronic acids occur in nature with six carbon atoms, and their names are based on the corresponding hexose. The name “glucuronic acid,” for example, derives from “glucose.”

Uronic acids are constituents of many important biopolymers of plant and animal origin. D-glucuronic acid is a component of hemicelluloses, gums, hyaluronic acid, and heparin; D-galacturonic acid, which is the monomeric unit of pectic substances, is a constituent of certain bacterial polysaccharides. The biosynthesis of uronic acids occurs with the participation of nucleoside diphosphate sugars and involves the oxidation of the—CH₂OH radical of the monosaccharide. In animals, D-glucuronic acid (found in the blood and urine) removes toxic substances by forming glycosides; the acid is also the starting material in the biosynthesis of absorbic acid.

REFERENCE

Khimiia uglevodov. Moscow, 1967. Chapter 10.

L. V. BAKINOVSKII

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References in periodicals archive

Sample Total carbohydrate (%) Uronic acid (%) Protein (%) RGP1 92.0 [+ or -] 1.3 4.2 [+ or -] 0.3 ND RGP2 73.1 [+ or -] 1.5 13.6 [+ or -] 0.4 ND RGP3 80.0 [+ or -] 0.5 17.8 [+ or -] 0.6 ND RGP4 72.4 [+ or -] 0.3 8.4 [+ or -] 0.6 ND ND = not detected.

Physicochemical Characterization of Polysaccharides with Macrophage Immunomodulatory Activities Isolated from Red Ginseng (Panax ginseng C. A. Meyer)

Soluble and insoluble dietary fibre monomers in the raw material and faeces were characterized using GLC for analysis of neutral sugars and spectrophotometry for analysis of uronic acids [33].

Formation of short-chain fatty acids, excretion of anthocyanins, and microbial diversity in rats fed blackcurrants, blackberries, and raspberries

Chondroitinases (chondroitinase AC-II, ABC, etc.) are very useful for the determination of GAG structures that are sulfated at various positions.41) Therefore, at the non-reducing terminus of a GAG chain, it is necessary to change unsaturated uronic acid to saturated uronic acid.

Synthesis of neoproteoglycans using the transglycosylation reaction as a reverse reaction of endo-glycosidases

A gas chromatographic method for the determination of aldose and uronic acid constituents of plant cell wall polysaccharides.

Bupleurum Chinense DC polysaccharides attenuates lipopolysaccharide-induced acute lung injury in mice

Sialic acid, glycosaminoglycans (GAGs) and uronic acid content

Effect of antler development stage on the chemical composition of velvet antler in elk (Cervus elaphus canadensis)

Principal Component 3 accounted for 16.2% of the variation and was negative for xylose and positive for glucose and uronic acids. Principal Component 4 accounted for 9.1% of the variation and was negative for uronic acids.

Relationships between soybean seed cell wall polysaccharides, yield, and seed traits. (Crop Physiology & Metabolism)

Barrett, "Combined enzymatic and colorimetric method for determining the uronic acid and methylester content of pectin: application to tomato products," Food Chemistry, vol.

Isolation and Characterization of Pectic Polysaccharide Fraction from In Vitro Suspension Culture of Fumaria officinalis L

This acidic nature indicates that the mucilage contains uronic acids in its structure.

Extraction and Physicochemical Characterization of Mucilage from Opuntia cochenillifera (L.) Miller

Heparin is a SP member of a family of glycosaminoglycans widely used as anticlotting and antithrombotic drug, consisting of 1,4-linked residues of uronic acid and D-glucosamine.

Structural features and inactivation of coagulation proteases of a sulfated polysaccharidic fraction from Caulerpa cupressoides var. lycopodium (Caulerpaceae, Chlorophyta)/Caracteristicas estruturais e inativacao de proteases da coagulacao de uma fracao polissacaridica sulfatada de Caulerpa cupressoides var. lycopodium (Caulerpaceae; Chlorophyta)

The investigators used size exclusion chromatography analysis, carbohydrate analysis and uronic acid assay profiling of the collected fractions to determine the differences between the middle lamella and cell wall pectin.

Differential degradation of pectin may be linked to fruit quality

Uronic acid polysaccharide components were measured colorimetrically in an aliquot from the first step of the acid-hydrolysis procedure using galacturonic acid as the calibration standard (Ahmed and Labavitch, 1977).

Alfalfa stem tissues: cell wall deposition, composition, and degradability. (Forage & Grazing Lands)

Yield (% delignified Fraction material) Extracted with DMSO 9.65 Extracted with NaOH 11.03 Table 2: The contents of neutral sugars and uronic acid (relative%, w/w) of hemicellulosic fractions obtained from DMSO-extracted and NaOH-extracted hemicelluloses.

Fractionation of DMSO-Extracted and NaOH-Extracted Hemicelluloses by Gradient Ethanol Precipitation from Neosinocalamus affinis