Polysaccharides neutral sugar

ChSS was fractionated on a column (550 x 15 mm) of DEAE Sepharo e Fast Flow using a Hiload System (Pharmacia), which was initially equilibrated in 0.005 M NaAc-bufFer pH 5.0. The sample was dissolved in water, the insoluble residue was removed by centrifugation and the supernatant was applied onto the column. After applying the gradient shown in Figure 1, the residual polysaccharides were washed from the column using 0.5 M NaOH. Fractions (23 ml) were collected and assayed by automated methods [2,3] for total neutral sugars and uronic acids. 

Rha, Ara and Gal are the neutral sugar components from all the fractions. Xyl is not present in Fla and is significantly present in the hemicellulose fractions, indicating that this monosaccharide is component of hemicellulosic polymers. Chemical composition of the water fractions were determined (Table V). High protein contents and the presence of O-acetyl-groups were observed in four aqueous fractions. Neutral sugar and uronic acid composition points to inclusion of these polymers in the class of pectic polysaccharides. 

Gel chromatography on Sephadex GlOO (2.8x50cm) of polysaccharide fraction I (Sample 2). The polysaccharide fraction was dissolved in a phosphate buffer at pH 6. After centrifugation, the supernatant was applied to the column at a flow rate of 0.8 ml/min. The elution was performed with a phosphate buffer and fractions of 10 ml each were collected. The refraction of each fraction was measured interferometrically. Fractions with coincident peaks were collected and analyzed for content of galacrturonic acid, neutral sugars and protein. 

Characteristics of fraction I. The carbohydrate content of Fraction I was 84.4 %, in which the main component is D-galacturonic acid (71 %). Consequently, the polysaccharide is of a pectic type. The neutral sugars accounted for 13.4 % and according to their qualitative composition (Table 2) they correspond to the composition of pectin, isolated from sunflower heads (18). It is worth noting the high content of L-arabinose and D-galactose, compared with the other monosaccharides. The protein content was 7.8 %. 

Polysaccharide fi-action 3 also manifested biological activity. It contained the highest percentage of neutral sugars (78.6%) mainly L-arabinose and D-galactose. Most probably, this is a polysaccharide of pectinoarabinogalactan type. 

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... 

CD. see Circular dichroism Cell wall polysaccharides isolation of plant cell walls and fractionation, 697-718 neutral sugars, determination by GC of alditol acetates, 721 -732 pectin... 

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