Pectin hydrolysate

Figure 1. Size-exclusion chromatography on TSK HW-40 of pectin hydrolysate from pea shoot cell wall. The fractions (1 ml each) were pooled as indicated. 0 - Uronic acids, A - pentoses, x - hexoses.

After multistep fractionation of cell wall pectin hydrolysate several bioactive fractions were obtained. They exhibited various influence on process of root development in buckwheat thin cell-layer (BTCL) explants (Table 1). 

For apple maceration, the main activity is the endopectinlyase (PL) which decreases the viscosity due to the colloidal pectin by decreasing tlie molecular weight of this substrate methylated at about 90%. In association to this PL, exo B and endoarabanase (ARAs), pectinacetylesterase (PAE), rhamnogalacturonase (RG) and other hemicellulases allow to hydrolyse side chains of the pectin, decrease the steric hindrance and make the access of pectinases to the rhamnogalacturonic backbone more easy. 

Marsh grapefhiit (MGF) pulp was homogenized in 5 volumes of extraction buffer at 4 C and maintained at pH 8.0 (28). The homogenate was stirred for one hour, centrifuged and the supernatant used as the PE extract. Activity was measured by titration with a Brinkman (Westbury, NY) pH stat titrator at pH 7.5 and 30°C in 25 mL of 1 % high methoxyl pectin (Citrus Colloids Limited, Hereford, UK) with O.IM NaCl. PE units are expressed as the microequivalents of ester hydrolysed per minute. Uronic acid analyses were conducted based on the m-phenyl phenol (4) as modified for microplate reading (30). 

This paper reports on the separation of some fragments obtained by acid hydrolyses of pectin from pea shoot cell walls, which had effect on thin cell-layer explant rhizogenesis. 

Plant material fractionation. The detailed steps of isolation and separation of oligosaccharide fractions were described earlier [10]. Pectin was separated by boiling the cell walls in 0.5 M ammonium-oxalate buffer, pH 5.2 at 100 C for Ih. The dialyzed solution of pectin was hydrolyzed with 0.15M HCl for 3h at 100 C. Neutralized and desalted hydrolysate was loaded to the column (lx90cm) filled with biogel TSK HW-40 (Toyo Soda, Japan) equilibrated and eluted with 50mM sodium acetate (pH 5.2) at a rate of 0.3ml/min. In all fractions (1ml) the sugars were determined by o-toluidine method (Resnikov et al., 1982) and fraction IP was collected as shown on Figure 1. 

Murata Y, Miyashita M, Kofuji K, et al. Drug release properties of a gel bead prepared with pectin and hydrolysate. Control Release 2004 95(1) 61-66. 

Dietary fibre consists of all components of plant cell walls not digested by human alimentary enzymes. Chemically, fibre is a mixture of cellulose, lignin, heteropoly-saccharides (hemicelluloses), acidic polysaccharides and pectin. In the colon, bacteria hydrolyse up to 15% of cellulose and 70-95% of other polysaccharides giving rise to volatile gases and low molecular weight fatty acids (acetic, butyric etc.) which have weak laxative activity. In addition the cellulosic and non-cellulosic polysaccharides are hydrophilic and absorb large amounts of fluid from the gut lumen, increasing in bulk as they do so. This is exactly the... 

The degradation of the pectin main chain is catalysed not only by pectinases, which hydrolyse the glycosidic link, but also by lyases, which carry out and iilcB-like elimination across C4 and C5, leaving a 4-deoxy-4,5-dehydro-galacturonic acid at the new non-reducing end (see Section 6.7.4). 

Two major groups of pectin degrading enzymes are the hydrolases (EC 3.2.1.15), which hydrolyse the galacturonan moiety, and the lyases (EC... 

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