Description
(2S)-2-amino-3-(3,4-dihydroxyphenyl)propanoic acid, crystalline powder, 1000 mg pack. Material intended exclusively for laboratory and analytical in vitro research. The product is not intended for human or animal consumption; it is not a medicinal product, food supplement, foodstuff or cosmetic.
Three distinct entities that must not be confused
For this molecule, separating the layers is particularly important, because the same chemical name stands both for one of the longest-used medicines in neurology and for the reagent sold on this page. Three contexts, three entirely different legal statuses:
| Entity | What it is | What it concerns |
|---|---|---|
| Chemical substance L-DOPA (Levodopa), CAS 59-92-7 |
A chemical concept — a molecule of defined structure. In itself it is neither a medicine nor a reagent; its status is conferred only by the form in which it has been manufactured and authorised. | chemistry, substance registries |
| Medicinal product historical trade names: Larodopa, Dopar, Bendopa, Brocadopa, Dopaidan, Dopalina, Dopasol, Eldopal, Insulamina, Pardopa, Cidandopa, Dopaflex, Maipedopa |
A pharmaceutical preparation: a defined pharmaceutical form, manufacture under GMP, registration dossier, safety surveillance. The substance is the active ingredient of medicines used for decades in Parkinson’s disease, usually in combination with a peripheral decarboxylase inhibitor (carbidopa or benserazide). In Poland it is dispensed only on prescription. | clinical studies involving humans concerned this entity |
| Chemical reagent material offered here |
Material for laboratory and analytical work. It does not and cannot hold any authorisation for use in humans or animals — it has no pharmaceutical form and no medicinal product documentation. | analytics, chemistry, reference standards |
The consequence is unambiguous. The research results cited further on this page were obtained either with the registered medicinal product (clinical studies involving humans, the history of Parkinson’s disease treatment), or with the substance under laboratory conditions — in studies of plants, enzymes or analytical methods, without administering it to humans or animals. None of these studies was conducted with the analytical reagent offered on this page, and none of these results transfers to the material offered. The reagent is not a form in which the substance was ever administered to humans, and it cannot be used in such a way.
Reagent identification sheet
| Systematic name (IUPAC) | (2S)-2-amino-3-(3,4-dihydroxyphenyl)propanoic acid |
|---|---|
| Common name | L-DOPA, Levodopa (Lewodopa) |
| CAS number | 59-92-7 |
| Molecular formula | C9H11NO4 |
| Molar mass | 197.19 g·mol−1 |
| Monoisotopic mass | 197.0688 Da |
| InChIKey | WTDRDQBEARUVNC-LURJTMIESA-N |
| SMILES | C1=CC(=C(C=C1CC(C(=O)O)N)O)O |
| PubChem CID | 6047 |
| ChEMBL | CHEMBL3663399 |
| Melting point | 285 °C (PubChem data, CID 6047) |
| Form | crystalline powder, white to off-white |
| Purity | ≥ 99% |
| Intended use | research reagent — not for human or animal consumption |
Lineage of the molecule: from legumes to a breakthrough in neurology
L-DOPA is not a molecule designed in the laboratory — it is a natural, non-proteinogenic amino acid, isolated from plants before it was synthesised. It occurs in young shoots of the broad bean (Vicia faba) and in the seeds of several leguminous plants of the genus Mucuna, including Mucuna pruriens (velvet bean) — it is these seeds that today remain the main plant source of the molecule used in research on its biosynthesis and on methods for its determination [6][7].
From isolation to oral therapy
The pharmacological history of the molecule is well documented in the review literature [1][2][3]. The link between the plant molecule and a neurodegenerative disease proved crucial: in the mid-20th century the hypothesis of a role for dopamine in the central nervous system was formulated, and its deficiency was subsequently demonstrated in the striatum of the brains of people who had died with Parkinson’s disease. Because dopamine itself does not cross the blood–brain barrier, attention turned to its direct metabolic precursor, which is able to cross this barrier. The first attempts to administer L-DOPA to patients were intravenous, and the breakthrough came only with the development of an oral regimen, which showed lasting improvement in the motor symptoms of Parkinson’s disease [2][3]. Since then levodopa has been the point of reference for the pharmacotherapy of Parkinson’s disease — always in the form of a registered medicinal product, never in the form of an analytical reagent.
A dopamine precursor — why this particular molecule
L-DOPA is the direct metabolic precursor of dopamine: the conversion is carried out by the enzyme aromatic L-amino acid decarboxylase (AADC, also called DOPA decarboxylase), which cleaves off the carboxyl group of the molecule. This is the same class of enzymes that produces serotonin from 5-hydroxytryptophan — which is why 5-HTP, offered separately, is sometimes cited as a molecule analogous in terms of the enzymatic pathway, despite the different arrangement of substituents on the aromatic ring. An earlier link in the same biosynthetic pathway is in turn L-tyrosine, from which L-DOPA is formed by tyrosine hydroxylase through the addition of a second hydroxyl group to the ring.
Timeline
| 1913 | isolation of L-DOPA from young shoots of the broad bean (Vicia faba) — one of the first works on this amino acid in plant chemistry |
|---|---|
| 1950s | formulation of the hypothesis of a role for dopamine in the central nervous system [1] |
| 1960 | detection of dopamine deficiency in the striatum of the brains of patients with Parkinson’s disease [1] |
| 1961 | first intravenous administrations of L-DOPA to patients as part of experimental studies [2] |
| 1967 | demonstration of the efficacy of oral administration — a turning point for the pharmacotherapy of Parkinson’s disease [3] |
| 1970s–1980s | registrations as a medicinal product in successive countries; introduction of combination preparations with a peripheral decarboxylase inhibitor |
| 2011–2019 | development of quantitative methods for determining L-DOPA in Mucuna pruriens seeds: HPTLC [6], analysis of the biosynthetic pathway [7], quantitative NMR [8] |
| 2024 | description of the dynamics of L-DOPA accumulation in the broad bean at the level of gene expression [9] |
| 2019–2026 | development of electrochemical biosensors and methods for chiral recognition of L-DOPA/D-DOPA [14][11][12] |
Directions of current research
The literature on L-DOPA is not concentrated around a single centre — activity is today spread across three independent directions: the biochemistry of leguminous plants (why Mucuna pruriens and the broad bean accumulate L-DOPA in their seeds [7][9]), analytical chemistry (L-DOPA as a classic analyte for methods with electrochemical detection [10][13]) and chiral recognition — sensors that distinguish L-DOPA from D-DOPA without chromatographic separation [11][12], building on the enzymatic basis of this distinction [5].
Chemistry: a catechol amino acid with a stereogenic centre at the α-carbon
Why the L form, not the D form, matters biochemically
The molecule has one stereogenic centre — the α-carbon of the amino acid, to which four different substituents are attached: the amino group, the carboxyl group, a hydrogen atom and the catechol substituent. The designation (2S) in the IUPAC name corresponds to the designation L- in traditional amino acid nomenclature, in line with the rule that applies to most natural proteinogenic and non-proteinogenic amino acids. The D-DOPA enantiomer exists and is available as a separate standard, but it is not the form used by the enzymes of the catecholamine pathway.
This distinction is not purely theoretical. The work of Wu and co-workers showed that D-DOPA is not simply metabolically inert — it is unidirectionally converted to L-DOPA by an enzymatic route, first by D-amino acid oxidase and then by dopa transaminase [5]. For a laboratory working with both standards, this means that the mere presence of an L-DOPA signal in a biological sample does not establish which form was originally administered — a method that separates the enantiomers is needed [11][12].
The catechol group: electroactivity and susceptibility to oxidation
The second structural hallmark is the catechol (ortho-dihydroxybenzene) ring. The two adjacent hydroxyl groups on the aromatic ring are readily oxidised to the ortho-quinone form — this susceptibility to oxidation makes L-DOPA an exceptionally good analyte for electrochemical detection (low oxidation potential, a strong and selective signal against the biological matrix background) and explains the number of recent papers on electrodes and biosensors dedicated to this molecule [13][14]. The same reactivity has a practical consequence for storage of the material — see the section below.
Physicochemical characteristics
| Parameter | Value | What follows from it |
|---|---|---|
| Partition coefficient (XLogP) | ≈ −2.7 | strong hydrophilicity — the molecule elutes early in RP-HPLC, the opposite behaviour to most of the catalogue |
| Topological polar surface area | 104 Å2 | very high for a molecule of this size — a result of the amino, carboxyl and two hydroxyl groups |
| Hydrogen bond donors | 4 | the amino group, the carboxyl group and the two catechol hydroxyls |
| Hydrogen bond acceptors | 5 | carboxyl oxygen (×2) and two catechol oxygens, plus the nitrogen |
| Solubility | good in water and dilute acids; poor in non-polar organic solvents | prepare stock solutions in acidified water or in dilute acid, not in the organic solvents typical for the rest of the catalogue |
Nomenclature and synonyms: why “DOPA” is an abbreviation
The name DOPA derives from the first letters of the German term for dihydroxyphenylalanine — the abbreviation caught on faster than the full systematic name and today functions as the common name in most languages, including Polish. The prefix L- distinguishes the natural enantiomer from its mirror image, D-DOPA.
Several equivalent designations of the same molecule with CAS number 59-92-7 are in chemical and bibliographic use:
- L-DOPA / Levodopa / Lewodopa — the most common names in Polish and international use;
- L-3,4-dihydroxyphenylalanine — the expansion of the abbreviation DOPA;
- (-)-3,4-Dihydroxyphenylalanine — an older designation using the optical rotation sign (-) instead of the prefix L-, found in the earlier chemical literature before R/S nomenclature became widespread;
- 3-Hydroxy-L-tyrosine / L-Tyrosine, 3-hydroxy- — names emphasising the relationship with L-tyrosine, from which the molecule is formed biosynthetically;
- Alanine, 3-(3,4-dihydroxyphenyl)-, L- — older designation in the Chemical Abstracts convention;
- (2S)-2-amino-3-(3,4-dihydroxyphenyl)propanoic acid — systematic IUPAC name, the only unambiguous one.
Historical trade names of pharmaceutical preparations containing this active substance are listed only in the table separating the entities at the top of the page — they are not synonyms of the reagent offered and should not be treated as such when ordering laboratory material.
Laboratory applications of the reagent
- reference material for confirming identity and purity by HPLC-UV and by HPLC with electrochemical detection (HPLC-ED), naturally suited to the electroactive catechol group;
- standard in methods for determining L-DOPA alongside related catecholamines and metabolites in biological matrices [10];
- material for chiral methods that distinguish L-DOPA from D-DOPA — nanozymes and photoelectrochemical architectures [11][12];
- comparative material for the quantitative determination of L-DOPA content in plant material (Mucuna pruriens seeds, broad bean) by HPTLC and NMR [6][8];
- calibration compound in the development of electrodes and biosensors for continuous monitoring of L-DOPA concentration [13][14];
- model compound in studies of the chemistry of catechol amino acids and their susceptibility to oxidation.
Storage, handling and occupational safety
Store in the original, tightly closed container in a dry, cool place protected from light, separately from food and animal feed and out of the reach of children. Because the catechol group is susceptible to oxidation, avoid prolonged exposure to air and light after opening the container. Work only under laboratory conditions using personal protective equipment: gloves, safety glasses and laboratory clothing; weigh the powder under conditions that limit dust formation. Avoid inhaling dust and contact with skin and eyes. Dispose of waste in accordance with the regulations applicable to chemical waste at the place where the research is carried out.
Hazard classification (PubChem data). Pictograms GHS07, GHS08, GHS09; hazard statement H302 (harmful if swallowed); signal word: Danger; precautionary statement P203 according to the source classification. Read the current Safety Data Sheet before starting work.
Regulatory status
The substance is the active substance of medicinal products used for decades in Parkinson’s disease, dispensed in Poland on prescription — usually as combination preparations with a peripheral aromatic amino acid decarboxylase inhibitor (carbidopa or benserazide). Trade in medicinal preparations is subject to separate pharmaceutical law and this offer does not concern it. The material offered is a chemical reagent and holds no authorisation for any use in humans or animals. The purchaser is responsible for ensuring that the intended use complies with the law in force in the country of destination.
Frequently Asked Questions
How does L-DOPA differ from D-DOPA?
They are a pair of enantiomers differing in configuration at the α-carbon. The natural form, used by the enzymes of the catecholamine pathway, is designated L- (2S configuration). D-DOPA is metabolically converted unidirectionally to L-DOPA by an enzymatic route, rather than being simply inert.
What are the chemical formula and molar mass of L-DOPA?
C9H11NO4; molar mass 197.19 g·mol−1, monoisotopic mass 197.0688 Da. CAS number 59-92-7, InChIKey WTDRDQBEARUVNC-LURJTMIESA-N.
Are Levodopa and L-DOPA the same substance?
Yes, they are two common names for the same molecule with CAS number 59-92-7. Levodopa is the international non-proprietary name (INN), L-DOPA is an abbreviation of the chemical name — both are used interchangeably in the literature.
Where does the name “DOPA” come from?
It is an abbreviation of dihydroxyphenylalanine. The prefix L- indicates the spatial configuration of the natural enantiomer, as distinct from the mirror-image form D-DOPA.
Where does L-DOPA come from naturally?
It is a natural non-proteinogenic amino acid occurring in several leguminous plants — above all in the seeds of Mucuna pruriens and in young shoots of the broad bean (Vicia faba). It is this plant material that is the subject of research on the biosynthesis and content of L-DOPA [7][9].
Why is L-DOPA a convenient analyte for electrochemical detection?
Because of the catechol group, which oxidises at a relatively low potential, giving a strong, selective electrochemical signal. The same property accounts for the large number of papers on electrodes and biosensors dedicated to this molecule.
Is the reagent suitable for anything other than laboratory use?
No. The material is intended exclusively for laboratory and analytical research. It is not intended for human or animal consumption; it is not a medicine, food supplement, food or cosmetic, and must not be used for medical, diagnostic or consumption purposes.
How should L-DOPA be stored as a laboratory reagent?
In the original, tightly closed container, in a dry, cool place protected from light, separately from food and animal feed and out of the reach of children. Because the catechol group is susceptible to oxidation, the time of exposure to air after opening the container should additionally be limited.
What should L-DOPA be dissolved in to prepare a stock solution?
It dissolves well in water and dilute acids, and poorly in non-polar organic solvents — the opposite of most of our catalogue. With an XLogP of ≈ −2.7, stock solutions are prepared in an aqueous phase, preferably slightly acidified.
How is the purity of L-DOPA confirmed?
By HPLC-UV or HPLC with electrochemical detection against a reference material. A chiral method is required to distinguish the L and D forms — a total determination alone does not settle this.
Is a safety data sheet supplied with L-DOPA?
We provide the safety data sheet on request to recipients engaged in research or analytical activity.
Is L-DOPA legal in Poland?
L-DOPA is the active substance of medicinal products dispensed in Poland on prescription; trade in medicines is subject to separate regulations and this offer does not concern it. The material offered is a chemical reagent with no authorisation for use in humans. The purchaser is responsible for ensuring that the intended use complies with the law of the country of destination.
What is an L-DOPA standard used for in the analytical laboratory?
For confirming identity and purity by HPLC-UV/HPLC-ED, as a standard for determining content in plant material, as material for chiral methods distinguishing L-DOPA from D-DOPA, and as a calibration compound in the development of electrochemical biosensors.
References
The entries come from the PubMed database and concern the research history, chemistry, plant biochemistry and analytics of this molecule — this is the complete list of sources used in preparing this page as of 2026-09-06. Entries [1]–[4] are review papers on the history of levodopa as a medicinal product; [5] is an enzymatic study on the conversion of D-DOPA to L-DOPA; [6]–[9] are papers on plant biochemistry and analytics (Mucuna pruriens, Vicia faba); [10]–[14] are methodological papers in analytical chemistry and bioanalytics. None of them describes the use of the analytical reagent offered on this page — they are cited as scientific context and bibliographic guidance, not as information on the properties of the material offered, nor as an encouragement to any use.
- Hornykiewicz O (2010). “A brief history of levodopa.” J Neurol. PMID 21080185. doi:10.1007/s00415-010-5741-y.
- Fahn S (2008). “The history of dopamine and levodopa in the treatment of Parkinson’s disease.” Mov Disord. PMID 18781671. doi:10.1002/mds.22028.
- Lees AJ, Tolosa E, Olanow CW (2015). “Four pioneers of L-dopa treatment: Arvid Carlsson, Oleh Hornykiewicz, George Cotzias, and Melvin Yahr.” Mov Disord. PMID 25488030. doi:10.1002/mds.26120.
- Whitfield AC, Moore BT, Daniels RN (2014). “Classics in chemical neuroscience: levodopa.” ACS Chem Neurosci. PMID 25270271. doi:10.1021/cn5001759.
- Wu M, Zhou XJ, Konno R, Wang YX (2006). “D-dopa is unidirectionally converted to L-dopa by D-amino acid oxidase, followed by dopa transaminase.” Clin Exp Pharmacol Physiol. PMID 17042912. doi:10.1111/j.1440-1681.2006.04484.x.
- Raina AP, Khatri R (2011). “Quantitative Determination of L-DOPA in Seeds of Mucuna Pruriens Germplasm by High Performance Thin Layer Chromatography.” Indian J Pharm Sci. PMID 22707835. doi:10.4103/0250-474X.95651.
- Singh SK, Dhawan SS, Lal RK et al. (2018). “Biochemical characterization and spatio-temporal analysis of the putative L-DOPA pathway in Mucuna pruriens.” Planta. PMID 30105476. doi:10.1007/s00425-018-2978-7.
- Fernandez-Pastor I, Luque-Muñoz A, Rivas F et al. (2019). “Quantitative NMR analysis of L-Dopa in seeds from two varieties of Mucuna pruriens.” Phytochem Anal. PMID 30216583. doi:10.1002/pca.2793.
- Jena S, Sanyal R, Jawed DM et al. (2024). “Spatio-temporal expression of polyphenol oxidase unveils the dynamics of L-DOPA accumulation in faba bean (Vicia faba L.).” Physiol Mol Biol Plants. PMID 38846459. doi:10.1007/s12298-024-01449-2.
- Bugamelli F, Marcheselli C, Barba E, Raggi MA (2011). “Determination of L-dopa, carbidopa, 3-O-methyldopa and entacapone in human plasma by HPLC-ED.” J Pharm Biomed Anal. PMID 21035976. doi:10.1016/j.jpba.2010.09.042.
- Yuan Y, Luo D, Shi L et al. (2026). “Chiral D/L-His@Cu NPs with peroxidase-like activity for colorimetric detection of D/L-DOPA.” Anal Methods. PMID 42418172. doi:10.1039/d6ay00528d.
- Zhang W, Wang H, Du C et al. (2026). “A Triple-Functional CuO@PANI@l-His Architecture for Nanozyme-Enhanced Photoelectrochemical Chiral Sensing of DOPA Enantiomers.” Anal Chem. PMID 41720588. doi:10.1021/acs.analchem.5c08070.
- Probst D, Batchu K, Younce JR, Sode K (2024). “Levodopa: From Biological Significance to Continuous Monitoring.” ACS Sens. PMID 39047295. doi:10.1021/acssensors.4c00602.
- Goud KY, Moonla C, Mishra RK et al. (2019). “Wearable Electrochemical Microneedle Sensor for Continuous Monitoring of Levodopa: Toward Parkinson Management.” ACS Sens. PMID 31403773. doi:10.1021/acssensors.9b01127.
Identification data and computed descriptors from PubChem (CID 6047) and the ChEMBL registry.
Related reagents in our catalogue
- L-Tyrosine — the direct biosynthetic precursor of L-DOPA; the conversion is carried out by tyrosine hydroxylase
- 5-HTP — a substrate of the same class of decarboxylating enzymes (AADC), but in the serotonin rather than the catecholamine pathway
- L-Phenylalanine — an earlier link in the same biosynthetic pathway, with one hydroxyl group fewer than L-tyrosine
Statement of intended use
The material offered is a chemical reagent intended exclusively for research, analytical and laboratory purposes. It is not intended for human or animal consumption. It is not a medicinal product, food supplement, foodstuff, medical device or cosmetic. It must not be used for medical, diagnostic, therapeutic, prophylactic or consumption purposes, administered to humans or animals, applied to the skin, or added to food, beverages or animal feed. Sold exclusively to recipients engaged in research, scientific or analytical activity who have laboratory facilities and the knowledge required to handle chemical reagents safely. The purchaser bears sole responsibility for the lawful and safe use of the reagent and for compliance with the regulations in force in the country of destination.
