Galacturonic acid preparation

Reduced galacturonic acid and oligogalacturonides (GalU-oI, diGalU-ol, triGalU-ol and pentaGalU-ol) were prepared by NaBH, reduction of the corresponding alduronic acids. For NMR experiments the compounds were lyophilized three times from D2O. 

A series of crystalline salts of D-galacturonic acid has recently been prepared by Isbell and Frush.62 Some of these, e. g., calcium sodium D-galacturonate, are suitable for the separation of D-galacturonic acid from plant materials. 

The major pathway probably proceeds via D-galacturonic acid and L-galactono-1,4-lactone, as these are converted to L-ascorbic acid by mitochondria prepared from peas and mung beans, but neither L-gulono-1,4-... 

The sugar composition of the pectic polysaccharides obtained from these cell wall preparations (Table II) also suggested differences in the structural features of the different cell wall preparations. Detailed structural information is only available for the pectic polysaccharides obtained from the endosperm cell wall The main fraction of endosperm pectic polysaccharide was separated into two fractions, a neutral sugar-rich fraction and a fraction with a very high content of D-galacturonic acid (8). Structural... 

Double-tail derivatives were sometimes prepared by short syntheses thus, dithioacetals 9 were obtained by condensation of a free carbohydrate with the corresponding -alkanethiol [50] whereas the 6,6-di-O-alkyl derivatives 29 were synthesized by the reaction of alkyl magnesium bromide with l,2 3,4-di-0-iso-propylidene-D-galacturonic acid [62]. 

In potato pectic polysaccharides, the RG-I domain accounts for 75% of the total, a much higher proportion than in pectic polysaccharides of other species ( 20-35%) (Oomen et al., 2003 Mohnen et al., 2008). RG-1 consists of a backbone of alternating a-D-galacturonic acid and a-L-rhamnosyl residues, linked as indicated in Figure 3.3, which in potato accounts for 14% of the total RG-1 (Oomen et al., 2003). Although the galacturonic acid residues are probably not methyl-esterified, they may be acetylated. This is so in potato, where a preparation... 

When treated with 5% sulfuric acid for 1.5 hours at 150°, pectin and D-galacturonic acid give reductic acid in yields of approximately 10% it is also formed on treatment of alginic acid with acid.96,119 The original preparation from pectin has been improved by using ion-exchange techniques,110 and synthetic preparations have been developed.188... 

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