The Chemistry and Biochemistry of Pectic Substances

Worth, H. G. J.

doi:10.1021/cr60248a005

Cited by 48 publications

(16 citation statements)

References 61 publications

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“…The data of both the sycamore and bean cell wall preparations is predominantly galacturonic acid. This material also contains some arabinose, galactose, and rhamnose, sugars which have previously been shown to be covalently linked in pectin (21).…”

Section: Resultsmentioning

confidence: 96%

A Cell Wall-degrading Endopolygalacturonase Secreted by Colletotrichum lindemuthianum

et al. 1972

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Cultures of Colletotrichum lindertmuthianum (Saccardo and Magnus) Scribner have been induced to secrete an endopolygalacturonase (polygalacturonide glyeanohydrolase EC3.2. 1.15). This enzyme has been brought to a high state of purity bv ion exchange, gel filtration, and agarose affinity chromatography. The enzyme has optimal activity at pH 5, has an apparent molecular weight as determined bv gel filtration of about 70,000, and prefers polygalacturonic acid to pectin as its substrate. The enzymne, while hydrolyzing only 1% of the glycosidic bonds, reduces the viscosity of a polygalacturonic solution by 50 %. Nevertheless, the initial as well as the final products of polygalacturonic acid hydrolysis are predominantly tri-and digalacturonic acid and, to a lesser extent, monogalacturonic acid. The purified enzyme catalyzes the removal of about 80% of the galacturonic acid residues of cell walls isolated from suspension-cultured sycamore cells (Acer pseudoplatanus) as well as from the walls isolated from 8-day-old Red Kidney bean (Phaseolus vulgaris) hypocotvls.Most polysaccharide-degrading enzymes are unable to attack effectively their substrates within isolated cell walls. Evidence has been presented which suggests that the "wall-modifying enzyme" purified from the culture filtrate of Aspergillus niger is a polygalacturonic acid-degrading enzyme (13). Treatment of walls with the wall-modifying enzyme permits other enzymes to degrade their substrates within the wall. Additional evidence that polygalacturonic acid-degrading enzymes are probably able, without assistance, to degrade cell walls comes from numerous efforts to demonstrate that these enzymes macerate plant tissues (2,4,5,7,12,18,20

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Section: Resultsmentioning

confidence: 96%

A Cell Wall-degrading Endopolygalacturonase Secreted by Colletotrichum lindemuthianum

et al. 1972

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“…The presence of pectic polysaccharides in the primary cell walls of dicots has been known for a long time (19,31). RG-II, a pectic polymer accounting for 4% of suspension cultured sycamore cell walls, has been shown to contain at least 15 differently linked glycosyl residues.…”

Section: Discussionmentioning

confidence: 99%

Structure of Plant Cell Walls

McNeil¹,

Darvill²,

Albersheim³

1980

Plant Physiol.

231

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The purification and characterization of a pectic polymer, rhamnogalacturonan I, present in the primary cell walls of dicots is described. Rhamnogalacturonan I accounts for approximately 7% of the mass of the walls isolated from suspension-cultured sycamore cells. As purified, rhamnogalacturonan I has a molecular weight of approximately 200,000 and is composed primarily of L-rhamnosyl, D-galacturonosyl, L-arabinosyl, and Dgalactosyl residues. The backbone of rhamnogalacturonan I is thought to be composed predominantly of D-galacturonosyl and L-rhamnosyl residues in a ratio of approximately 2:1. About half of the L-rhamnosyl residues are 2-linked and are glycosidically attached to C4 of a D-galacturonosyl residue.The other half of the L-rhamnosyl residues are 2,4-inked and have a Dgalacturonosyl residue glycosidically attached at C2. Sidechains averaging 6 residues in length are attached to C4 of the L-rhamnosyl residues. There are many different sidechains, containing variously linked L-arabinosyl, and/or n-galactosyl residues.Pectic polysaccharides are defined as those containing 4-linkeda-D-galacturonosyl residues (25). Pectic polysaccharides are important components of the primary cell walls of dicots, accounting for approximately 30% of the walls (8,20,25,28 Enzyme Purification. Endo-a-1,4-polygalacturonase was purified from Colletotrichum lindemuthianum (15) and checked for purity as described (I 1).Enzymic Extraction of Pectic Polysaccharides. The pectic polysaccharides were extracted from isolated sycamore cell walls by C. lindemuthianum endopolygalacturonase by the procedures de-Gel Filtration Chromatography. Gel filtration chromatography was performed on a 1.4-x 40-cm agarose A-1.Sm column or on a 3-x 50-cm agarose A-Sm column. The columns were equilibrated and eluted with 50 mm Na-acetate (pH 5.2). The void and included volumes of the columns were determined with blue dextran (Sigma) and NaCl, respectively. In some cases (as noted in the text), the agarose A-1.5m column was equilibrated and eluted with 50 mm Na-acetate ( Analysis of Glycosyl and Glycosyl-linkage Compositions. The neutral and amino glycosyl compositions were determined by the alditol acetate method (1, I 1). Glycosyl-linkage compositions were determined by GC and GC-MS analysis of the partially methylated alditol acetate derivatives (9, 28). Polysaccharide methylations were performed using modifications (11,28,30)

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“…Beet pulp contains high amounts of pectic polysaccharides that consist of a-1,4-D-galacturonan, a highly branched L-arabinan, and a/b-1,4-galactan (Worth, 1967). The pectins contain both structural and non-structural carbohydrates.…”

Section: --mentioning

confidence: 99%

Effects of pressed beet pulp silage inclusion in maize-based rations on performance of high-yielding dairy cows and parameters of rumen fermentation

Boguhn

Kluth

Bulang

et al. 2010

Animal

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Beet pulp contains high amounts of pectins that can reduce the risk of rumen disorders compared to using feedstuffs high in starch. The objective was to study the effects of inclusion of ensiled pressed beet pulp in total mixed rations (TMR) for highyielding dairy cows. Two TMR containing no or about 20% (on dry matter (DM) basis) beet pulp silage were used. The beet pulp silage mainly replaced maize silage and corn cob silage. The TMR were intentionally equal in the concentrations of energy and utilisable crude protein (CP) at the duodenum. TMR were fed to 39 and 40 dairy cows, respectively, for 118 days. The average daily milk yield was about 43 kg/day. No significant differences in milk yield and milk fat or milk protein content were detected. DM intake of cows was significantly reduced by the inclusion of beet pulp silage (23.0 v. 24.5 kg/day). However, a digestibility study, separately conducted with sheep, showed a significantly higher organic matter digestibility and metabolisable energy concentration for the TMR that contained beet pulp silage. In vitro gas production kinetics indicated that the intensity of fermentation was lower in the TMR that contained beet pulp silage. In vitro production of short-chain fatty acids, studied using a Rusitec, did not differ between the TMR. However, the inclusion of beet pulp silage in the ration caused a significant reduction in the efficiency of microbial CP synthesis in vitro. The amino acid profile of microbial protein remained unchanged. It was concluded that beet pulp silage has specific effects on ruminal fermentation that may depress feed intake of cows but improve digestibility. An inclusion of beet pulp silage of up to 20% of DM in rations for high-yielding dairy cows is possible without significant effects on milk yield and milk protein or milk fat.

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The Chemistry and Biochemistry of Pectic Substances

Cited by 48 publications

References 61 publications

A Cell Wall-degrading Endopolygalacturonase Secreted by Colletotrichum lindemuthianum

A Cell Wall-degrading Endopolygalacturonase Secreted by Colletotrichum lindemuthianum

Structure of Plant Cell Walls

Effects of pressed beet pulp silage inclusion in maize-based rations on performance of high-yielding dairy cows and parameters of rumen fermentation

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