l-DOPA, also known asl-3,4-dihydroxyphenylalanine and used medically aslevodopa, is made and used as part of the normalbiology of some plants^[2] and animals, including humans. Humans, as well as a portion of the other animals that utilizel-DOPA, make it viabiosynthesis from theamino acidl-tyrosine.

L-DOPA

Skeletal formula ofL-DOPA
Ball-and-stick model of thezwitterionic form ofL-DOPA found in thecrystal structure[1]
Names
IUPAC name (S)-2-Amino-3-(3,4-dihydroxyphenyl)propanoic acid
Other names l-3,4-Dihydroxyphenylalanine; Levodopa
Identifiers
CAS Number	59-92-7
3D model (JSmol)	Interactive image
ChEBI	CHEBI:15765
ChEMBL	ChEMBL1009
ChemSpider	5824
DrugBank	DB01235
ECHA InfoCard	100.000.405
EC Number	200-445-2
KEGG	C00355
PubChemCID	6047
UNII	46627O600J
CompTox Dashboard(EPA)	DTXSID9023209
InChI InChI=1S/C9H11NO4/c10-6(9(13)14)3-5-1-2-7(11)8(12)4-5/h1-2,4,6,11-12H,3,10H2,(H,13,14)/t6-/m0/s1 Key: WTDRDQBEARUVNC-LURJTMIESA-N
SMILES C1=CC(=C(C=C1C[C@@H](C(=O)O)N)O)O
Properties
Chemical formula	C9H11NO4
Molar mass	197.19 g/mol
Except where otherwise noted, data are given for materials in theirstandard state (at 25 °C [77 °F], 100 kPa). Infobox references

l-DOPA is theprecursor to theneurotransmittersdopamine,norepinephrine (noradrenaline), andepinephrine (adrenaline), which are collectively known ascatecholamines. Furthermore,l-DOPA itself mediatesneurotrophic factor release by the brain and CNS.^[3][4] In some plant families (of the orderCaryophyllales),l-DOPA is the central precursor of a biosynthetic pathway that produces a class of pigments calledbetalains.^[5]

l-DOPA can be manufactured and in its pure form is sold as adrug with theINNTooltip International Nonproprietary Namelevodopa. Trade names include Sinemet, Pharmacopa, Atamet, and Stalevo. As a drug, it is used in thetreatment ofParkinson's disease anddopamine-responsive dystonia, as well asrestless leg syndrome.^[6]

l-DOPA has a counterpart with oppositechirality,d-DOPA. As is true for many molecules, the human body produces only one of theseisomers (thel-DOPA form). Theenantiomeric purity ofl-DOPA may be analyzed by determination of the optical rotation or by chiralthin-layer chromatography.^[7]

l-DOPA is produced from the amino acidl-tyrosine by the enzymetyrosine hydroxylase.l-DOPA can act as anl-tyrosine mimetic and be incorporated into proteins by mammalian cells in place ofl-tyrosine, generatingprotease-resistant andaggregate-prone proteinsin vitro and may contribute toneurotoxicity with chronicl-DOPA administration.^[11]It is also the precursor for themonoamine orcatecholamine neurotransmitters dopamine, norepinephrine (noradrenaline), and epinephrine (adrenaline). Dopamine is formed by the decarboxylation ofl-DOPA byaromaticl-amino acid decarboxylase (AADC).

l-DOPA can be directly metabolized bycatechol-O-methyl transferase to3-O-methyldopa, and then further tovanillactic acid. This metabolic pathway is nonexistent in the healthy body, but becomes important after peripherall-DOPA administration in patients with Parkinson's disease or in the rare cases of patients with AADC enzyme deficiency.^[12]

l-Phenylalanine,l-tyrosine, andl-DOPA are all precursors to the biologicalpigmentmelanin. The enzymetyrosinasecatalyzes theoxidation ofl-DOPA to the reactive intermediatedopaquinone, which reacts further, eventually leading to melaninoligomers. In addition,tyrosinase can convert tyrosine directly tol-DOPA in the presence of a reducing agent such asascorbic acid.^[13]

l-dopa was first islolated from the seeds of theVicia faba orbroad bean plant in 1913 by Swiss biochemist Markus Guggenheim.^[14]

The 2001Nobel Prize in Chemistry was also related tol-DOPA: the Nobel Committee awarded one-quarter of the prize toWilliam S. Knowles for his work on chirally catalysedhydrogenation reactions, the most noted example of which was used for the synthesis ofl-DOPA.^[15][16][17]

l-DOPA is a keycompound in the formation ofmarine adhesive proteins, such as those found inmussels.^[18][19] It is believed to be responsible for the water-resistance and rapid curing abilities of these proteins.l-DOPA may also be used to prevent surfaces from fouling by bonding antifouling polymers to a susceptiblesubstrate.^[20] The versatile chemistry ofl-DOPA can be exploited in nanotechnology.^[21] For example, DOPA-containing self-assembling peptides were found to form functional nanostructures, adhesives and gels.^{[22][23][24][25]}

In plants, L-DOPA functions as anallelochemical which inhibits the growth of certain species, and is produced and secreted by a few legume species such as the broad beanVicia faba and the velvet beanMucuna pruriens.^[26] Its effect is strongly dependent on the pH and the reactivity of iron in the soil.^[27] L-DOPA can also be found incephalopod ink.^[28]

L-DOPA is used medically under the namelevodopa in the treatment ofParkinson's disease and certain other medical conditions. It is usually used incombination with aperipherally selectivearomaticL-amino acid decarboxylase (AAAD)inhibitor such ascarbidopa orbenserazide. These agents increase the strength and duration of levodopa. Combination formulations includelevodopa/carbidopa andlevodopa/benserazide, as well aslevodopa/carbidopa/entacapone.

L-DOPA is found in high amounts inMucuna pruriens (velvet bean) and is available and usedover-the-counter as asupplement.