MetaCyc Compound Class: a pectate

Synonyms: Poly(1,4-α-D-galacturonate)(n), (1,4-α-D-galacturonosyl)n, 1,4-α-D-galacturonide, a pectic acid, an α-D-polygalacturonic acid, a poly(1,4-α-D-galacturonate)

Superclasses: all carbohydrates a carbohydrate a glycan a polysaccharide a galacturonan a modified galacturonan

A pectin is a structural heteropolysaccharide consisting of a complex set of polysaccharides that is present in most primary cell walls and is particularly abundant in the non-woody parts of terrestrial plants. The characteristic structure of pectin is a linear chain of α-(1-4)-linked D-galacturonate that forms the pectin-backbone, a homogalacturonan.

Diferent types of pectin have different substitutions and additions. A common type is rhamnogalacturonan I, where some D-galacturonate units are replaced by (1-2)-linked L-rhamnose, to which side chains of various neutral sugars branch off, mostly D-galactose, L-arabinose and α-D-xylopyranose.

In nature, around 80% of the carboxyl groups of the galacturonate units are esterified with methanol. Some plants like sugar beet, potatoes and pears contain pectins with acetylated galacturonic acid in addition to methyl esters.

Partially esterified pectins are often refered to as pectinate, and if the degree of esterification is below 5%, as a pectate.

a pectate compound structure

a pectate compound structure

Child Classes: a pectate oligosaccharide with 4-(4-deoxy-α-D-galact-4-enuronosyl)-D-galacturonate end (0)

SMILES: C1(C(C([O-])=O)OC(C(C1O)O)OC3(C(C(=O)[O-])OC(OC2(C(C(=O)[O-])OC([R2])C(C2O)O))C(C3O)O))[R1]

Unification Links: ChEBI:33885 , HMDB:HMDB03363 , KEGG:G00276 , PubChem:445929

Reactions known to consume the compound:

pectin degradation II :
a pectate + H2O → a pectate + α-D,α-D-digalacturonate

pectin degradation III :
(1,4-α-D-galacturonide)n + H2O → D-galactopyranuronate + (1,4-α-D-galacturonide)(n-1)

Not in pathways:
a pectatea pectate + Δ4,5-unsaturated trigalacturonate

Not in pathways:
a polysaccharide + H2O → an oligosaccharide

Reactions known to produce the compound:

pectin degradation II , pectin degradation III :
a pectin + n H2O → a pectate + n methanol

cellulose and hemicellulose degradation (cellulolosome) :
a feruloyl-polysaccharide + H2O → ferulate + a polysaccharide + H+

Not in pathways:
an N-acetyl-β-D-galactosalaminyl-[glycan] + H2O → a glycan + N-acetyl-β-D-galactosamine

In Reactions of unknown directionality:

Not in pathways:
a pectate = a pectate + 4-(4-deoxy-α-D-galact-4-enuronosyl)-D-galacturonate
a pectate = a pectate + a pectate oligosaccharide with 4-(4-deoxy-α-D-galact-4-enuronosyl)-D-galacturonate end

Revised 14-Mar-2013 by Caspi R , SRI International


Richard09: Richard P, Hilditch S (2009). "D-galacturonic acid catabolism in microorganisms and its biotechnological relevance." Appl Microbiol Biotechnol 82(4);597-604. PMID: 19159926

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Please cite the following article in publications resulting from the use of MetaCyc: Caspi et al, Nucleic Acids Research 42:D459-D471 2014
Page generated by SRI International Pathway Tools version 19.0 on Tue Apr 28, 2015, biocyc13.