-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 Pectic acid, also known as polygalacturonic acid, is a water-soluble, transparent gelatinous acid existing in over-ripe fruit and some vegetables. It is a product of pectin degradation in plants, and is produced via the interaction between pectin ...

. 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 Mucic acid, C6H10O8 or HOOC-(CHOH)4-COOH (galactaric acid or meso-galactaric acid) is an aldaric acid obtained by nitric acid oxidation of galactose or galactose-containing compounds such as lactose, dulcite, quercite, and most varieties of gu ...

) (carboxylic groups at C1 and C6). It is also a

uronic acid 300px, The glucose.html" ;"title="Fischer projections of D-glucose">Fischer projections of D-glucose (left) and D-glucuronic acid (right). Glucose's terminal carbon's primary alcohol group has been oxidized to a carboxylic acid. Uronic acids ...

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 -Iduronic acid (IUPAC abbr.: IdoA) is the major uronic acid component of the glycosaminoglycans (GAGs) dermatan sulfate, and heparin. It is also present in heparan sulfate, although here in a minor amount relative to its carbon-5 epimer glucuronic ...

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