Description

L-Cysteine, n-[(9H-Fluoren-9-Ylmethoxy)Carbonyl]-S-[(2-Nitrophenyl)Methyl]- is a sophisticated, orthogonally protected derivative of the essential amino acid L-cysteine, designed for advanced peptide synthesis and biochemical research. This compound is critical for researchers and manufacturers requiring precise control over cysteine reactivity during complex molecular assembly, particularly in solid-phase peptide synthesis (SPPS). It is primarily utilized by pharmaceutical R&D teams, biotechnology companies, and academic institutions focused on developing peptide-based therapeutics, diagnostic probes, and biochemical tools.

Application

• Solid-Phase Peptide Synthesis (SPPS): Serves as a key building block for the controlled incorporation of cysteine residues, where the Fmoc and Npys protecting groups allow for selective deprotection and disulfide bond formation.
• Pharmaceutical Intermediate: Used in the research and development of peptide drugs, including hormones, antimicrobial peptides, and targeted therapeutics that require specific disulfide bridge patterns for stability and activity.
• Bioconjugation and Probe Development: The reactive S-(2-nitrophenylsulfenyl) (Npys) group enables efficient thiol-disulfide exchange, making it valuable for labeling proteins, creating antibody-drug conjugates (ADCs), or synthesizing fluorescent or affinity probes.
• Biochemical Research: Employed in studies of protein folding, enzyme mechanisms, and redox biology where the specific modification or protection of cysteine thiol groups is required.
• Combinatorial Chemistry Libraries: A valuable component for generating diverse peptide libraries for high-throughput screening in drug discovery campaigns.

Basic Information

Product Name	L-Cysteine, n-[(9H-Fluoren-9-Ylmethoxy)Carbonyl]-S-[(2-Nitrophenyl)Methyl]-
CAS No.	476639-82-4
Molecular Formula	C25H22N2O5S
Molecular Weight	462.52 g/mol
Synonyms	Fmoc-Cys(Npys)-OH; N-α-Fmoc-S-(2-nitrophenylsulfenyl)-L-cysteine; Fmoc-Cysteine(Npys)-OH; N-Fmoc-S-(2-nitrophenylsulfenyl)cysteine; Fmoc-L-Cys(Npys)-OH; L-Cysteine, N-[(9H-fluoren-9-ylmethoxy)carbonyl]-S-[(2-nitrophenyl)methyl]-; Nα-Fmoc-Npys-cysteine
EINECS	Contact for details

Quality Control

Our Fmoc-Cys(Npys)-OH is manufactured under strict quality systems to ensure batch-to-batch consistency and high purity, essential for reproducible results in sensitive synthetic applications. Each lot undergoes comprehensive analytical testing, including HPLC for purity and chiral integrity, NMR for structural confirmation, and mass spectrometry. Certificates of Analysis (COA) detailing all specifications are provided and available upon request.

Storage

Preserve in a tightly closed container, protected from light. Store at -20°C or below in a freezer. This compound is hygroscopic (moisture-sensitive) and should be allowed to equilibrate to room temperature in a desiccator before opening to prevent condensation and hydrolysis.

Specification

Item	Specification
Appearance	White to pale yellow crystalline powder
Identification (HPLC)	Conforms
Identification (NMR)	Conforms
Purity (HPLC)	≥ 98.0%
Optical Rotation [α]	Contact for details
Water Content (KF)	≤ 1.0%
Heavy Metals	≤ 20 ppm

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