Description

Fmoc-Cys(Et)-Oh is a protected cysteine derivative where the thiol group is protected with an ethyl (Et) moiety and the α-amino group is protected with a 9-fluorenylmethoxycarbonyl (Fmoc) group. This compound is a critical building block in solid-phase peptide synthesis (SPPS), enabling the controlled incorporation of cysteine residues while preventing unwanted side reactions. It is essential for researchers and manufacturers in the pharmaceutical, biotechnology, and life sciences sectors developing therapeutic peptides, peptide hormones, and diagnostic agents.

Application

• Solid-Phase Peptide Synthesis (SPPS): A key protected amino acid for the automated, stepwise synthesis of complex peptides and proteins.
• Pharmaceutical Intermediates: Used in the research and production of peptide-based drugs, including anticancer, antiviral, and metabolic disorder therapeutics.
• Bioconjugation and Labeling: The protected thiol group allows for site-specific deprotection and subsequent conjugation with fluorescent dyes, polymers, or other biomolecules.
• Research & Development: Serves as a standard reagent in academic and industrial R&D for studying protein structure, function, and peptide mimetics.
• Combinatorial Chemistry: Employed in libraries for high-throughput screening to discover new bioactive peptide leads.
• Disulfide Bond Formation: After deprotection, enables the formation of intramolecular or intermolecular disulfide bridges, crucial for the correct folding and stability of many bioactive peptides.

Basic Information

Product Name	Fmoc-Cys(Et)-Oh
CAS No.	200354-34-3
Molecular Formula	C₂₁H₂₃NO₄S
Molecular Weight	385.48 g/mol
Synonyms	Fmoc-S-ethyl-L-cysteine; N-[(9H-Fluoren-9-ylmethoxy)carbonyl]-S-ethyl-L-cysteine; Fmoc-L-Cys(Et)-OH; Fmoc-Cys(Et)-OH; (2R)-2-(9H-fluoren-9-ylmethoxycarbonylamino)-3-ethylsulfanylpropanoic acid; Fmoc-Cysteine(Ethyl)-OH; N-Fmoc-S-ethylcysteine; Fmoc-S-Et-Cys-OH
EINECS	Contact for details

Quality Control

Our Fmoc-Cys(Et)-Oh is manufactured under strict quality management systems. Each batch undergoes rigorous analytical testing, including HPLC for purity, chiral analysis for enantiomeric excess, and comprehensive identification tests. A detailed Certificate of Analysis (COA) is provided with each shipment, ensuring compliance with customer specifications and industry standards for peptide synthesis reagents.

Storage

Preserve in a tightly closed container, protected from light. Store in a cool, dry place at 2-8°C. This product is hygroscopic (moisture-sensitive) and should be handled under anhydrous conditions to maintain stability and purity.

Specification

Item	Specification
Appearance	White to off-white crystalline powder
Identification (IR)	Conforms to structure
Identification (HPLC)	Conforms to reference
Assay (HPLC)	≥98.5%
Optical Rotation [α]²⁰D	Contact for details
Water Content (KF)	≤0.5%
Heavy Metals	≤10 ppm
Residual Solvents (GC)	Complies with ICH guidelines

Note: Specifications can be tailored. Please contact us for the detailed technical data sheet of a specific grade.