L-Cysteine
Also known as: Cysteine, Cys, H-Cys-OH, 2-Amino-3-mercaptopropanoic acid, (R)-2-Amino-3-mercaptopropionic acid, (R)-Cysteine, Thioserine, L-β-Mercaptoalanine, alpha-Amino-beta-thiolpropionic acid
L-Cysteine (CAS 52-90-4) is a compound in the Organic Acids category listed in the Jingsj chemical database. It has the molecular formula C3H7NO2S and a molecular weight of 121.158 g/mol. Key properties include a melting point of 220 °C (dec.)(lit.), a boiling point of 293.9±35.0 °C at 760 mmHg, a density of 1.3±0.1 g/cm3 and a flash point of 131.5±25.9 °C. No supplier offers are currently listed; request a quote. Record last updated Aug 21, 2026.
- CAS No.
- 52-90-4
- Jingsj CID
- J-1401597-7
- Molecular Formula
- C3H7NO2S
- Molecular Weight
- 121.158 g/mol
- Category
- Organic Acids
- Last updated
- 8/21/2026
No offers for this compound yet.
Request a quotePhysicochemical Properties
| Melting Point | 220 °C (dec.)(lit.) |
|---|---|
| Boiling Point | 293.9±35.0 °C at 760 mmHg |
| Density | 1.3±0.1 g/cm3 |
| Flash Point | 131.5±25.9 °C |
| Exact Mass | 121.019745 |
| PSA | 102.12000 |
| LogP | 0.23 |
| Vapor Pressure | 0.0±1.3 mmHg at 25°C |
| Refractive Index | 1.550 |
| Additional Property | 280 g/L (25 ºC) |
Activity & Biological Data
| Target | Human Endogenous Metabolite |
|---|---|
| Additional Information | [1]. McGavigan AK, et al. L-cysteine suppresses ghrelin and reduces appetite in rodents and humans. Int J Obes (Lond). 2015 Mar;39(3):447-55. |
Customs & Trade Information
| HS Code | 2930909090 |
|---|---|
| Summary | 2930909090. other organo-sulphur compounds. VAT:17.0%. Tax rebate rate:13.0%. . MFN tariff:6.5%. General tariff:30.0% |
Frequently Asked Questions
What is the CAS number of L-Cysteine?
The CAS number of L-Cysteine is 52-90-4.
What are the molecular formula and molecular weight of L-Cysteine?
L-Cysteine has molecular formula C3H7NO2S and molecular weight 121.158 g/mol.
What are the upstream and downstream products of L-Cysteine?
For L-Cysteine, Upstream Products: L-Cysteine hydrochloride anhydrous, D-Cysteine, 3-Chloro-L-alanine; Downstream Products: L-Cysteinesulfinic acid, L-Cysteic acid, L-Cystine.
Data compiled from public chemical databases such as PubChem and supplier catalogs; supplier offers are provided by suppliers.
Last updated:
How to cite: Jingsj. "L-Cysteine (CAS 52-90-4)". Jingsj Chemical Database. https://www.jingsj.com/compound/J-1401597-7 (accessed 2026-11-07).
Data for reference only; verify product details with suppliers before purchase.