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.
Reactions known to consume the compound:
Not in pathways:
a pectate → a pectate + Δ4,5-unsaturated trigalacturonate
Reactions known to produce the compound:
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
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