-Galacturonic acid is a sugar acid, an oxidized form of
-galactose. It is the main component of
pectin
Pectin ( ': "congealed" and "curdled") is a heteropolysaccharide, a structural polymer contained in the primary lamella, in the middle lamella, and in the cell walls of terrestrial plants. The principal chemical component of pectin is galact ...
, in which it exists as the polymer
polygalacturonic acid.
In its open form, it has an
aldehyde
In organic chemistry, an aldehyde () (lat. ''al''cohol ''dehyd''rogenatum, dehydrogenated alcohol) is an organic compound containing a functional group with the structure . The functional group itself (without the "R" side chain) can be referred ...
group at C1 and a
carboxylic acid
In organic chemistry, a carboxylic acid is an organic acid that contains a carboxyl group () attached to an Substituent, R-group. The general formula of a carboxylic acid is often written as or , sometimes as with R referring to an organyl ...
group at C6. Other oxidized forms of -galactose are -galactonic acid (carboxylic group at C1) and ''meso''-galactaric acid (
mucic acid) (carboxylic groups at C1 and C6). It is also a
uronic acid or hexuronic acid. Naturally occurring uronic acids are -
glucuronic acid
Glucuronic acid (GCA, from ) is a uronic acid that was first isolated from urine (hence the name "uronic acid"). It is found in many natural gum, gums such as gum arabic ( 18%), xanthan, and kombucha tea and is important for the metabolism of ...
, -galacturonic acid, -
iduronic acid and -
mannuronic acid
Mannuronic acid is a uronic acid monosaccharide that can be derived from mannose. Along with -guluronic acid, -mannuronic acid is a component of alginic acid, a polysaccharide found predominantly in brown algae
Brown algae (: alga) are a lar ...
.
References
{{DEFAULTSORT:Galacturonic acid, D-
Uronic acids