Malic acid

Malic acid
	; DL-Malic acid
Names
	Preferred IUPAC name 2-Hydroxybutanedioic acid
	Other names Hydroxybutanedioic acid; 2-Hydroxysuccinic acid; (L/D)-Malic acid; (±)-Malic acid; (S/R)-Hydroxybutanedioic acid;
Identifiers
CAS Number	6915-15-7 ;
3D model ( JSmol)	Interactive image;
ChEBI	CHEBI:6650 ; CHEBI:30796 D-(+); CHEBI:30797 L-(–);
ChEMBL	ChEMBL1455497 ;
ChemSpider	510 ; 83793 D-(+)-malic acid ; 193317 L-(–)-malic acid ;
ECHA InfoCard	100.027.293
EC Number	230-022-8;
E number	E296 (preservatives)
IUPHAR/BPS	2480;
KEGG	C00711 ; C00497 D-(+); C00149 L-(–);
PubChem CID	525; 92824 D-(+); 222656 L-(–);
UNII	817L1N4CKP ;
CompTox Dashboard (EPA)	DTXSID0027640 ;
	InChI InChI=1S/C4H6O5/c5-2(4(8)9)1-3(6)7/h2,5H,1H2,(H,6,7)(H,8,9) Key: BJEPYKJPYRNKOW-UHFFFAOYSA-N ; InChI=1/C4H6O5/c5-2(4(8)9)1-3(6)7/h2,5H,1H2,(H,6,7)(H,8,9) Key: BJEPYKJPYRNKOW-UHFFFAOYAM;
	SMILES O=C(O)CC(O)C(=O)O;
Properties
Chemical formula	C4H6O5
Molar mass	134.09 g/mol
Appearance	Colorless
Density	1.609 g⋅cm−3
Melting point	130 °C (266 °F; 403 K)
Solubility in water	558 g/L (at 20 °C)
Acidity (pKa)	pKa1 = 3.40; pKa2 = 5.20; pKa3 = 14.5
Hazards
	GHS labelling:
Pictograms
Flash point	203 °C
Related compounds
Other anions	Malate
Related carboxylic acids	Succinic acid; Tartaric acid; Fumaric acid
Related compounds	Butanol; Butyraldehyde; Crotonaldehyde; Sodium malate
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). verify (what is ?) Infobox references

Malic acid is an

anion is a metabolic intermediate in the citric acid cycle

.

Etymology

The word 'malic' is derived from Latin mālum, meaning 'apple'. The related Latin word mālus, meaning 'apple tree', is used as the name of the genus Malus, which includes all apples and crabapples;^[5] and the origin of other taxonomic classifications such as Maloideae, Malinae, and Maleae.

Biochemistry

L-Malic acid is the naturally occurring form, whereas a mixture of L- and D-malic acid is produced synthetically.

L-Malic acid
D-Malic acid

Malate plays an important role in biochemistry. In the C4 carbon fixation process, malate is a source of CO₂ in the Calvin cycle. In the citric acid cycle, (S)-malate is an intermediate, formed by the addition of an -OH group on the si face of fumarate. It can also be formed from pyruvate via anaplerotic reactions.

Malate is also synthesized by the

phosphoenolpyruvate

in the guard cells of plant leaves. Malate, as a double anion, often accompanies potassium cations during the uptake of solutes into the guard cells in order to maintain electrical balance in the cell. The accumulation of these solutes within the guard cell decreases the solute potential, allowing water to enter the cell and promote aperture of the stomata.

In food

Malic acid was first isolated from apple juice by Carl Wilhelm Scheele in 1785.^[6] Antoine Lavoisier in 1787 proposed the name acide malique, which is derived from the Latin word for apple, mālum—as is its genus name Malus.^[7]^[8] In German it is named Äpfelsäure (or Apfelsäure) after plural or singular of a sour thing from the apple fruit, but the salt(s) are called Malat(e). Malic acid is the main acid in many fruits, including

ripeness. The taste of malic acid is very clear and pure in rhubarb, a plant for which it is the primary flavor. It is also the compound responsible for the tart flavor of sumac spice. It is also a component of some artificial vinegar flavors, such as "salt and vinegar" flavored potato chips.^[11]

The process of malolactic fermentation converts malic acid to much milder lactic acid. Malic acid occurs naturally in all fruits and many vegetables, and is generated in fruit metabolism.^[12]

Malic acid, when added to food products, is denoted by

INS number

296).

Malic acid contains 10 kJ (2.39 kilocalories) of energy per gram.^[16]

Production and main reactions

Racemic malic acid is produced industrially by the double hydration of maleic anhydride. In 2000, American production capacity was 5,000 tons per year. The enantiomers may be separated by chiral resolution of the racemic mixture. S-Malic acid is obtained by fermentation of fumaric acid.^[17]

fuming sulfuric acid gives the pyrone coumalic acid:^[18]

2 HO₂CCH(OH)CH₂CO₂H → HO₂CC₄H₃O₂ + 2 CO + 4 H₂O

Carbon monoxide and water are liberated during this reaction.

Malic acid was important in the discovery of the

Walden cycle, in which (−)-malic acid first is converted into (+)-chlorosuccinic acid by action of phosphorus pentachloride. Wet silver oxide

then converts the chlorine compound to (+)-malic acid, which then reacts with PCl₅ to the (−)-chlorosuccinic acid. The cycle is completed when silver oxide takes this compound back to (−)-malic acid.

L-malic acid is used to resolve α-phenylethylamine, a versatile resolving agent in its own right.^[19]

Plant defense

Soil supplementation with

soil amendment with molasses can be used as a crop treatment in horticulture.^[20]

Interactive pathway map

Click on genes, proteins and metabolites below to link to respective articles.[§ 1]

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|alt=Glycolysis and Gluconeogenesis edit]]

Glycolysis and Gluconeogenesis edit

^ The interactive pathway map can be edited at WikiPathways: "GlycolysisGluconeogenesis_WP534".

References

^ "chemBlink Database of Chemicals from Around the World". chemblink.com. Archived from the original on 2009-01-22.
OCLC 11865673
.

PMID 19288211
.

^ "DL-Malic acid - (DL-Malic acid) SDS". Merck Millipore.

^ Peffley, Ellen. "Peffley: Crabapples steal the show in autumn". Lubbock Avalanche-Journal. Retrieved 2022-08-08.

^ Carl Wilhelm Scheele (1785) "Om Frukt- och Bår-syran" (On fruit and berry acid), Kongliga Vetenskaps Academiens Nya Handlingar (New Proceedings of the Royal Academy of Science), 6 : 17-27. From page 21: " ... vil jag hådanefter kalla den Åple-syran." ( ... I will henceforth call it apple acid.)

^ de Morveau, Lavoisier, Bertholet, and de Fourcroy, Méthode de Nomenclature Chimique (Paris, France: Cuchet, 1787), p. 108.

ISSN 0021-9584
.

^ Tabelle I of "Fruchtsäuren". Wissenschaft Online Lexikon der Biologie. Archived from the original on May 15, 2016.

OCLC 16866762
.

^ "The Science Behind Salt and Vinegar Chips". seriouseats.com.

^ Malic Acid Archived 2018-06-25 at the Wayback Machine, Bartek Ingredients (retrieved 2 February 2012)

^ UK Food Standards Agency: "Current EU approved additives and their E Numbers". Retrieved 2011-10-27.

^ "Food Additive Status List". FDA. 26 August 2021. Retrieved 5 May 2022.

^ Australia New Zealand Food Standards Code"Standard 1.2.4 - Labelling of ingredients". 8 September 2011. Retrieved 2011-10-27.

ISBN 978-92-5-104949-5
. Retrieved 10 February 2014.

ISBN 978-3527306732
.

doi:10.15227/orgsyn.031.0023
.

doi:10.15227/orgsyn.017.0080
.

S2CID 221360634
.

External links

Calculator: Water and solute activities in aqueous malic acid

Retrieved from "https://en.wikipedia.org/w/index.php?title=Malic_acid&oldid=1217313615"

[WikiPathways-21] The interactive pathway map can be edited at WikiPathways: "GlycolysisGluconeogenesis_WP534".

[1] "chemBlink Database of Chemicals from Around the World". chemblink.com. Archived from the original on 2009-01-22.

[2] OCLC 11865673
.

[Silva_Kong_Hider_2009_pp._771–778-3] PMID 19288211
.

[4] "DL-Malic acid - (DL-Malic acid) SDS". Merck Millipore.

[5] Peffley, Ellen. "Peffley: Crabapples steal the show in autumn". Lubbock Avalanche-Journal. Retrieved 2022-08-08.

[6] Carl Wilhelm Scheele (1785) "Om Frukt- och Bår-syran" (On fruit and berry acid), Kongliga Vetenskaps Academiens Nya Handlingar (New Proceedings of the Royal Academy of Science), 6 : 17-27. From page 21: " ... vil jag hådanefter kalla den Åple-syran." ( ... I will henceforth call it apple acid.)

[7] Morveau, Lavoisier, Bertholet, and de Fourcroy, Méthode de Nomenclature Chimique (Paris, France: Cuchet, 1787), p. 108.

[8] ISSN 0021-9584
.

[9] Tabelle I of "Fruchtsäuren". Wissenschaft Online Lexikon der Biologie. Archived from the original on May 15, 2016.

[10] OCLC 16866762
.

[11] "The Science Behind Salt and Vinegar Chips". seriouseats.com.

[12] Malic Acid Archived 2018-06-25 at the Wayback Machine, Bartek Ingredients (retrieved 2 February 2012)

[13] UK Food Standards Agency: "Current EU approved additives and their E Numbers". Retrieved 2011-10-27.

[Food_Additive_Status_List-14] "Food Additive Status List". FDA. 26 August 2021. Retrieved 5 May 2022.

[15] Australia New Zealand Food Standards Code"Standard 1.2.4 - Labelling of ingredients". 8 September 2011. Retrieved 2011-10-27.

[FAO-16] ISBN 978-92-5-104949-5
. Retrieved 10 February 2014.

[17] ISBN 978-3527306732
.

[18] :10.15227/orgsyn.031.0023
.

[19] :10.15227/orgsyn.017.0080
.

[Rosskopf-et-al-2020-20] S2CID 221360634
.

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