Description

Lysyl-Arginyl-Arginyl-Phenylalanyl-Lysyl-Lysine is a synthetic hexapeptide with defined sequence and high structural specificity, widely employed in life science research and peptide-based therapeutic development. Its value lies in its role as a bioactive scaffold for protease substrate studies, receptor binding assays, and as an intermediate in the synthesis of larger functional peptides. Researchers in pharmaceutical R&D, academic biochemistry laboratories, and contract development and manufacturing organizations (CDMOs) rely on this compound for reproducible, high-fidelity experimental outcomes. Lysyl-Arginyl-Arginyl-Phenylalanyl-Lysyl-Lysine CAS NO 141363-42-0 is supplied under stringent quality controls to ensure batch-to-batch consistency and analytical traceability.

Application

• Substrate for trypsin-like serine proteases in enzymatic activity and inhibition assays
• Reference standard in HPLC and LC-MS method development for peptide quantification
• Building block in solid-phase peptide synthesis (SPPS) for custom therapeutic peptide sequences
• Tool compound in cell-based studies investigating arginine/lysine-rich motif interactions with nuclear transport receptors
• Calibration material for mass spectrometry instrument performance verification
• Component in assay kits for evaluating proteolytic cleavage efficiency and specificity
• Research use only (RUO) reagent in immunoassay development and epitope mapping
• Stability-indicating reference in forced degradation studies of peptide drug products

Basic Information

Product Name	Lysyl-Arginyl-Arginyl-Phenylalanyl-Lysyl-Lysine
CAS No.	141363-42-0
Molecular Formula	C₃₇H₆₄N₁₄O₈
Molecular Weight	825.00 g/mol
Synonyms	KRRFKK; Lys-Arg-Arg-Phe-Lys-Lys; H-Lys-Arg-Arg-Phe-Lys-Lys-OH; KRRFKK-OH; Hexapeptide KRRFKK; Nα-(tert-Butoxycarbonyl)-Lysyl-Arginyl-Arginyl-Phenylalanyl-Lysyl-Lysine (Boc-protected precursor); Peptide KRRFKK; RRKFKK (sequence variant notation, rarely used); Lysine-Arginine-Arginine-Phenylalanine-Lysine-Lysine
EINECS	Contact for details

Quality Control

Our products undergo rigorous quality testing to ensure compliance with industry standards. Certificates of Analysis (COA) are available upon request. All batches are tested for identity (by HPLC retention time and MS confirmation), purity (≥98.0% by HPLC), and absence of microbial contamination (bioburden testing per USP & Ph. Eur. guidelines). The manufacturing process adheres to ISO 9001-certified quality management systems and follows Good Manufacturing Practice (GMP)-aligned procedures appropriate for research-grade peptides.

Storage

Preserve in a tightly closed container, protected from light. Store at 2–8 °C for long-term stability. Due to its hygroscopic nature, minimize exposure to ambient humidity; allow the container to equilibrate to room temperature before opening to prevent condensation. Handle under inert atmosphere (e.g., nitrogen) when possible to mitigate potential oxidation.

Specification

Item	Specification
Appearance	White to off-white lyophilized powder
Identity (HPLC)	Retention time matches reference standard
Identity (MS)	[M+H]⁺ ion at m/z 825.5 ± 0.3
Assay (HPLC)	≥98.0%
Related Substances	Single impurity ≤0.5%; Total impurities ≤2.0%
Water Content (KF)	≤8.0%
Residual Solvents	MeOH ≤3000 ppm; Acetonitrile ≤400 ppm; TFA ≤50 ppm
Heavy Metals	≤10 ppm

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