Malic acid
IUPAC name	hydroxybutanedioic acid
Identifiers
CAS number	6915-15-7
EINECS number	230-022-8
Properties
Molecular formula	C4H6O5
Molar mass	134.09 g/mol
Density	1.609 g/cm³
Melting point	130C Malate is a district of Manila in the Philippines, under the 5th congressional district of Manila, divided into forty four (44) barangays from Zone 75 to 90 and barangays 686 to 730. ... Image File history File links No higher resolution available. ... IUPAC nomenclature is a system of naming chemical compounds and of describing the science of chemistry in general. ... CAS registry numbers are unique numerical identifiers for chemical compounds, polymers, biological sequences, mixtures and alloys. ... The EINECS number (for European Inventory of Existing Chemical Substances) is a registry number given to each chemical substance commercially available in the European Union between 1 January 1971 and 18 September 1981. ... A chemical formula is a concise way of expressing information about the atoms that constitute a particular chemical compound. ... Molar mass is the mass of one mole of a chemical element or chemical compound. ... For other uses, see Density (disambiguation). ... The melting point of a crystalline solid is the temperature range at which it changes state from solid to liquid. ...
Acidity (pKa)	pKa1 = 3.4, pKa2 = 5.13
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox disclaimer and references

Malic acid is a tart-tasting organic dicarboxylic acid that plays a role in many sour or tart foods. The salts and esters of malic acid are known as malates. Malate anion is an intermediate in the citric acid cycle along with fumarate. It can also be formed from pyruvate as one of the anaplerotic reactions. The acid dissociation constant (Ka), also known as the acidity constant or the acid-ionization constant, is a specific equilibrium constant for the reaction of an acid with its conjugate base in aqueous solution [1]. // When an acid dissolves in water, it partly dissociates forming hydronium ions and its conjugate... The plimsoll symbol as used in shipping In chemistry, the standard state of a material is its state at 1 bar (100 kilopascals exactly). ... A tart is a pastry dish, usually sweet, that is a type of pie, with an open top that is not covered with pastry. ... Benzene is the simplest of the arenes, a family of organic compounds An organic compound is any member of a large class of chemical compounds whose molecules contain carbon. ... Structure of a carboxylic acid The 3D structure of the carboxyl group A space-filling model of the carboxyl group Carboxylic acids are organic acids characterized by the presence of a carboxyl group, which has the formula -C(=O)OH, usually written -COOH or -CO2H. [1] Carboxylic acids are Bronsted... Human taste sensory organs, called taste buds or gustatory calyculi, and concentrated on the upper surface of the tongue, appear to be receptive to relatively few chemical species as tastes. ... A magnified crystal of salt In chemistry, salt is a term used for ionic compounds composed of positively charged cations and negatively charged anions, so that the product is neutral and without a net charge. ... For other uses, see Ester (disambiguation). ... Overview of the citric acid cycle The citric acid cycle (also known as the tricarboxylic acid cycle, the TCA cycle, or the Krebs cycle, after Hans Adolf Krebs who identified the cycle) is a series of chemical reactions of central importance in all living cells that use oxygen as part... Fumaric acid (IUPAC systematic name: 2-butenedioic acid), also called allomaleic acid, boletic acid or lichenic acid, is a colorless crystalline flammable carboxylic acid based on butene and molecular formula C4H4O4. ... Pyruvate (CH3COCOO−) is the ionized form of pyruvic acid. ... - of Greek origin, meaning to fill up Anaplerotic reactions are those that form intermediates of the TCA or citric acid cycle. ...

History

Malic acid was first isolated from apple juice by Carl Wilhelm Scheele in 1785. Antoine Lavoisier in 1787 proposed the name acide malique which is derived from the latin word for apple, malum.^[1] A glass of clear apple juice, from which pectin and starch have been removed. ... Carl Wilhelm Scheele Scheeles house with his pharmacy in Köping. ... Antoine-Laurent de Lavoisier (August 26, 1743 – May 8, 1794), the father of modern chemistry [1], was a French nobleman prominent in the histories of chemistry, finance, biology, and economics. ... For other uses, see Latin (disambiguation). ...

Biology

Malate is an important chemical compound in biochemistry. In biological sources, malic acid is homochiral and only exists as the (-)-malic acid enantiomer. In the C4 carbon fixation process, malate is a source of CO₂ in the Calvin cycle. Look up chemical compound in Wiktionary, the free dictionary. ... Biochemistry (from Greek: , bios, life and Egyptian kÄ“me, earth[1]) is the study of the chemical processes in living organisms. ... In chemistry, a molecule is chiral if it is not superimposable on its mirror image regardless of how it is contorted. ... In chemistry, enantiomers (from the Greek ἐνάντιος, opposite, and μέρος, part or portion) are stereoisomers that are nonsuperimposable complete mirror images of each other, much as ones left and right hands are the same but opposite. ... Overview of C4 carbon fixation C4 carbon fixation is one of three methods, along with C3 and CAM photosynthesis, used by land plants to fix carbon dioxide (binding the gaseous molecules to dissolved compounds inside the plant) for sugar production through photosynthesis. ... Carbon dioxide is a chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom. ... Overview of the Calvin cycle and carbon fixation The Calvin cycle (or Calvin-Benson cycle or carbon fixation) is a series of biochemical reactions that takes place in the stroma of chloroplasts in photosynthetic organisms. ...

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 dehydrogenase catalyzes the reversible conversion of malate into oxaloacetate using NAD as a cofactor. Overview of the citric acid cycle The citric acid cycle (also known as the tricarboxylic acid cycle, the TCA cycle, or the Krebs cycle, after Hans Adolf Krebs who identified the cycle) is a series of chemical reactions of central importance in all living cells that use oxygen as part... This article does not cite any references or sources. ... - of Greek origin, meaning to fill up Anaplerotic reactions are those that form intermediates of the TCA or citric acid cycle. ... Categories: Biochemistry stubs | EC 1. ... Nicotinamide adenine dinucleotide (NAD+ or in older notation DPN+) is an important coenzyme found in cells. ... A cofactor is the following: In mathematics a cofactor is the minor of an element of a square matrix. ...

Malate is also produced from starch in guard cells of plant leaves. A build up of malate leads to a low water potential. Water then flows into the guard cells causing the stoma to open. However, this process does not always induce the opening of stomas.

Apples contain malic acid, which contributes to the sourness of a green apple. Malic acid can make a wine taste tart, although the amount decreases with increasing fruit ripeness. The process of malolactic fermentation converts malic acid to much milder lactic acid. This article is about the fruit. ... For other uses, see Wine (disambiguation). ... Malolactic fermentation is a process of fermentation where tart malic acid is converted to softer-tasting lactic acid. ... For the production of milk by mammals, see Lactation. ...

As a food additive

Malic acid, when added to food products, is denoted by E number E296. Malic acid is the source of extreme tartness in so called "extreme candy", for example Mega Warheads. It is also used with or in place of the less sour citric acid in sour candies such as Jolly Ranchers, SweeTarts and Jimmy Johns Salt & Vinegar potato chips. These candies are sometimes labeled with a warning that excessive consumption can cause irritation of the mouth. For the mathematical constant see: E (mathematical constant). ... Warheads Juniors Extreme Sour packaging (Australian), showing one of each of the five flavors of candy. ... Citric acid is a weak organic acid found in citrus fruits. ... Jolly Rancher is a brand of candy, including hard candy, gummies, fruit chews, jellybeans, and lollipops. ... SweeTarts are sweet and sour candies invented by J. Fish Smith, the owner of Sunline. ...

Chemistry

Malic acid stars in the discovery of the Walden inversion and the Walden cycle in which (-)-malic acid first is converted into (+)-chlorosuccinic acid by action of phosphorus pentachloride. Wet silver oxide then takes 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. In chemistry Walden inversion is the inversion of configuration of a chiral centre in a molecule in a chemical reaction. ... Walden inversion is the inversion of a chiral center in a molecule in a chemical reaction. ... Phosphorus pentachloride is the chemical compound with the formula PCl5. ... This page is a candidate for speedy deletion, because: it is patent nonsense. ...

Self-condensation of malic acid with fuming sulfuric acid gives the pyrone coumalic acid:^[2] Self-condensation is an organic reaction where a chemical compound containing a carbonyl group acts both as the electrophile and the nucleophile in a aldol condensation. ... Sulfuric acid (British English: sulphuric acid), H2SO4, is a strong mineral acid. ... A pyrylium compound is a conjugated 6 membered carbon ring system with one carbon atom replaced by a positively charged oxygen atom forming a salt with a negatively charged counterion [1]. It is the oxygen pendant of benzene and shares with it aromatic properties. ...

Image File history File links No higher resolution available. ...

See also

• Malate-aspartate shuttle
• Two other dicarboxylic acids have similar names and should not be confused with malic acid:
  • Maleic acid
  • Malonic acid

The malate-aspartate shuttle (sometimes also the malate shuttle) is a system of two antiporter proteins located in the inner membrane of the mitochondrion in eukaryotes. ... Maleic acid or (Z)-Butenedioic acid or cis-butenedioic acid or malenic acid or maleinic acid or toxilic acid is an organic compound which is a dicarboxylic acid (molecule with two carboxyl groups). ... Malonic acid (IUPAC systematic name: propanedioic acid) is a dicarboxylic acid with structure CH2(COOH)2. ...

References

1. ^ The Origin of the Names Malic, Maleic, and Malonic Acid Jensen, William B. J. Chem. Educ. 2007, 84, 924. Abstract
2. ^ Richard H. Wiley and Newton R. Smith (1963). "Coumaric acid". Org. Synth.; Coll. Vol. 4: 201. 

v • d • e Citric Acid Cycle Metabolic Pathway
Oxaloacetate Malate Fumarate Succinate Succinyl-CoA Acetyl-CoA NADH + H+ NAD+ H2O FADH2 FAD CoA + ATP(GTP) Pi + ADP(GDP) + H2O NADH + H+ + CO2 CoA NAD+ H2O H2O NAD(P)+ NAD(P)H + H+ CO2 Citrate cis-Aconitate Isocitrate Oxalosuccinate α-Ketoglutarate