MetaCyc Compound Class: a pectin

Synonyms: pectin

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

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, including sugar beet, potatoes and pears, contain pectins with acetylated galacturonate in addition to methyl esters.

The salt of partially esterified pectins is called a pectinate, and if the degree of esterification is below 5%, a pectate.

a pectin compound structure

a pectin compound structure

Child Classes: methylesterified 1,4-α-D-galacturonosyl (0)

SMILES: COC(=O)C4(C([R1])C(O)C(O)C(OC3(C(C(O)=O)OC(OC2(C(O)C(O)C(OC1(C(C(=O)O)OC(O[R2])C(O)C(O)1))OC(C(=O)OC)2))C(O)C(O)3))O4)

Unification Links: CAS:9000-69-5 , ChEBI:17309 , HMDB:HMDB03402 , KEGG:C00714 , PubChem:451205 , Wikipedia:Pectin

Reactions known to consume the compound:

pectin degradation I :
a pectin → 4-(4-deoxy-α-D-galact-4-enuronosyl)-D-galacturonate

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

Not in pathways:
a polysaccharide + H2O → an oligosaccharide

Reactions known to produce the compound:

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 pectin = an oligosaccharide with 4-deoxy-6-O-methyl-α-D-galact-4-enuronate end + a pectin

Revised 31-Aug-2009 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 Sat May 30, 2015, biocyc14.