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MetaCyc Compound Class: a pectate

Synonyms: Poly(1,4-α-D-galacturonate)(n), (1,4-α-D-D-galactosyluronate)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

Summary:
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: an unsaturated pectate oligosaccharide (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 + an unsaturated pectate trisaccharide

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+

In Reactions of unknown directionality:

Not in pathways:
a pectate = a pectate + 4-(4-deoxy-α-D-galact-4-enuronosyl)-D-galacturonate
a pectate = n an unsaturated pectate oligosaccharide

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


References

Abbott08: Abbott DW, Boraston AB (2008). "Structural biology of pectin degradation by Enterobacteriaceae." Microbiol Mol Biol Rev 72(2);301-16, table of contents. PMID: 18535148

Caffall09: Caffall KH, Mohnen D (2009). "The structure, function, and biosynthesis of plant cell wall pectic polysaccharides." Carbohydr Res 344(14);1879-900. PMID: 19616198

HugouvieuxCotte96: Hugouvieux-Cotte-Pattat N, Condemine G, Nasser W, Reverchon S (1996). "Regulation of pectinolysis in Erwinia chrysanthemi." Annu Rev Microbiol 50;213-57. PMID: 8905080

MartensUzunova09: Martens-Uzunova ES, Schaap PJ (2009). "Assessment of the pectin degrading enzyme network of Aspergillus niger by functional genomics." Fungal Genet Biol 46 Suppl 1;S170-S179. PMID: 19618506

Reginault08: Reginault, Ph., Valette-Collet , O., Boccara, M. (2008). "The importance of fungal pectinolytic enzymes in plant invasion, host adaptability and symptom type." Eur. J. Plant Pathol.

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
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