L-Cysteine Aminoacid Purity >99,84% - 500g

L-Cysteine – Amino Acid >99.84%

Other Names: (S)-2-Amino-3-mercaptopropanoic acid, L-β-thiolalanine
Chemical Formula: C₃H₇NO₂S
Molar Mass: 121.16 g/mol
CAS Number: 52-90-4
Appearance: White crystalline powder
Odor: Characteristic sulfur or thiol-like odor

L-Cysteine is a naturally occurring sulfur-containing α-amino acid with a reactive thiol (-SH) side group. It plays a key role in thiol-disulfide chemistry, and is widely utilized in organic synthesis, redox chemistry, and biochemical research.

Chemical and Physical Properties

• Density: ~1.68 g/cm³

• Melting Point: ~240 °C (decomposes)

• Solubility in Water: Freely soluble (~25 g/100 mL at 20 °C)

• Solubility in Alcohol: Slightly soluble

• pKa Values:

  • pKa₁ (carboxyl): ~1.71

  • pKa₂ (amino): ~10.78

  • pKa₃ (thiol): ~8.33

• Isoelectric Point (pI): ~5.02

Applications

• Organic and Peptide Synthesis: Serves as a building block and nucleophilic reagent in thiol-based reactions.

• Redox Chemistry: Used as a reducing agent in analytical and preparative procedures.

• Biochemical Studies: Applied in enzyme assays, protein folding experiments, and metabolic research.

• Surface Functionalization: Suitable for modifying gold and metal surfaces via thiol self-assembled monolayers (SAMs).

Safety

Signal Word: ⚠️ Warning

Hazard Statements:

• H315: Causes skin irritation

• H319: Causes serious eye irritation

• H335: May cause respiratory irritation

Precautionary Statements:

• P261: Avoid breathing dust

• P280: Wear protective gloves/protective clothing/eye protection/face protection

• P305+P351+P338: IF IN EYES: Rinse cautiously with water for several minutes. Remove contact lenses if present and easy to do. Continue rinsing

• P337+P313: If eye irritation persists: Get medical advice/attention

• P501: Dispose of contents/container in accordance with local regulations

Handling and Storage

• Handling: Avoid dust generation and direct contact with skin or eyes. Use PPE and work in a ventilated environment.

• Storage: Store in a cool, dry, well-ventilated area in a tightly sealed container. Protect from moisture and heat.

Environmental Considerations

Not classified as environmentally hazardous in small quantities, but excessive release should be avoided. Dispose of in accordance with local environmental and chemical waste regulations.