FComEx: Citric acid (PC000115)

Record Information

Version

1.0

Creation date

2015-10-09 22:28:34 UTC

Update date

2017-01-19 02:36:13 UTC

FoodComEx ID

PC000115

FoodDB Record

FDB012586

Chemical Information

Name

Citric acid

Description

Citric acid (citrate) is a weak tricarboxylic acid that is formed in the tricarboxylic acid cycle. In humans citric acid is produced endogenously or it may be introduced with diet, with citrus fruits being a key source. Citrate is produced by all aerobic organisms, from microbes to humans. Citrate is formed in the TCA cycle via the enzyme known as citrate synthase, which catalyzes the condensation of oxaloacetate with acetyl CoA to form citrate. Citrate then acts as the substrate for aconitase and is converted into aconitic acid. Some bacteria (notably E. coli) can produce and consume citrate internally as part of their TCA cycle, but are unable to use it as food because they lack the enzymes required to import it into the cell. Citrate has a number of biological roles in humans. In particular, it can be transported out of the mitochondria and into the cytoplasm, then broken down into acetyl-CoA for fatty acid synthesis. Citrate can also acts as a signalling molecule. High concentrations of cytosolic citrate can inhibit phosphofructokinase, the catalyst of a rate-limiting step of glycolysis. Inhibition of glycolysis has been shown to suppress tumor growth in a number of animal models ( PMID: 28674429). Citrate is also a vital component of bone, helping to regulate the size of apatite crystals. Urinary citrate levels can be used to identify a number of disorders. Indeed urinary citrate excretion is a common tool in the differential diagnosis of kidney stones, renal tubular acidosis and it plays also a role in characterizing bone diseases such as osteoporosis (PMID 12957820). The secretory epithelial cells of the prostate gland of humans and other animals possess a unique citrate-related metabolic pathway regulated by testosterone and prolactin. This specialized hormone-regulated metabolic activity is responsible for the major prostate function of the production and secretion of extraordinarily high levels of citrate. The key regulatory enzymes directly associated with citrate production in the prostate cells are mitochondrial aspartate aminotransferase, pyruvate dehydrogenase, and mitochondrial aconitase. Testosterone and prolactin are involved in the regulation of the corresponding genes associated with these enzymes (PMID 12198595). In addition to its biological roles and endogenous production, citrate is obtained from many other sources and used in many applications. Citric acid is found in citrus fruits, most concentrated in lemons and limes, where it can comprise as much as 8% of the dry weight of the fruit. The concentrations of citric acid in citrus fruits range from 5 mM for oranges and grapefruits to 300 mM in lemons and limes. However, these values vary within species depending upon the cultivar and the circumstances in which the fruit was grown. Citric acid is a natural preservative and is also used to add an acidic (sour) taste to foods and soft drinks. Citric acid is used as an excipient in pharmaceutical preparations due to its antioxidant properties. It can be used to treat water, which makes it useful in improving the effectiveness of soaps and laundry detergents. Citric acid is also used as an acidulant in creams, gels, and liquids. The salts of citric acid (citrates) can be used as anticoagulants due to their calcium chelating ability. Intolerance to citric acid in the diet is known to exist. Altered levels of citric acid have been found to be associated with maple syrup urine disease, primary hypomagnesemia, propionic acidemia, and tyrosinemia I, which are inborn errors of metabolism.

CAS Number

77-92-9

Structure

MOL SDF PDB SMILES InChI

Synonyms

Synonym	Source
1,2,3-Propanetricarboxylic acid, 2-hydroxy- (9CI)	biospider
2-Hydroxy-1,2,3-propanetricarboxylate	biospider
2-Hydroxy-1,2,3-propanetricarboxylic acid	biospider
2-hydroxypropane-1,2,3-tricarboxylic acid	biospider
2-Hydroxypropanetricarboxylic acid	biospider
2-Hydroxytricarballylate	Generator
2-Hydroxytricarballylic acid	db_source
3-Carboxy-3-hydroxypentane-1,5-dioate	biospider
3-Carboxy-3-hydroxypentane-1,5-dioic acid	biospider
Aciletten	HMDB
Anhydrous citrate	HMDB
Anhydrous citric acid	HMDB
beta-Hydroxytricarballylate	HMDB
beta-Hydroxytricarballylic acid	HMDB
Chemfill	HMDB
Citraclean	HMDB
Citrate	biospider
Citretten	HMDB
Citro	HMDB
Citronensaeure	ChEBI
e 330	HMDB
E330	db_source
FEMA 2306	db_source
H3Cit	ChEBI
Hydrocerol a	HMDB
Kyselina citronova	HMDB
Suby g	HMDB
Uro-trainer	HMDB

Chemical Formula

C6H8O7

IUPAC name

2-hydroxypropane-1,2,3-tricarboxylic acid

InChI Identifier

InChI=1S/C6H8O7/c7-3(8)1-6(13,5(11)12)2-4(9)10/h13H,1-2H2,(H,7,8)(H,9,10)(H,11,12)

InChI Key

KRKNYBCHXYNGOX-UHFFFAOYSA-N

Isomeric SMILES

OC(=O)CC(O)(CC(O)=O)C(O)=O

Average Molecular Weight

192.1235

Monoisotopic Molecular Weight

192.02700261

Chemical Taxonomy

Description

Belongs to the class of organic compounds known as tricarboxylic acids and derivatives. These are carboxylic acids containing exactly three carboxyl groups.

Kingdom

Organic compounds

Super Class

Organic acids and derivatives

Class

Carboxylic acids and derivatives

Sub Class

Tricarboxylic acids and derivatives

Direct Parent

Tricarboxylic acids and derivatives

Alternative Parents