Enfuvirtide Acetate | CAS 159519-65-0 / 914454-00-5 | HIV-1 gp41 Fusion Inhibitor (Research Use Only) | Knowlux

Product Description

Enfuvirtide Acetate, CAS 159519-65-0 (free peptide) / 914454-00-5 (acetate salt), is a synthetic linear 36-amino-acid peptide corresponding to residues 127-162 of the HIV-1 gp41 ectodomain, supplied by Knowlux for laboratory research use. The sequence is Ac-Tyr-Thr-Ser-Leu-Ile-His-Ser-Leu-Ile-Glu-Glu-Ser-Gln-Asn-Gln-Gln-Glu-Lys-Asn-Glu-Gln-Glu-Leu-Leu-Glu-Leu-Asp-Lys-Trp-Ala-Ser-Leu-Trp-Asn-Trp-Phe-NH2. The molecular formula is C204H301N51O64 (free peptide) and the molecular weight is 4491.88 g/mol (free peptide basis). Each lot is released with a lot-specific COA, MSDS and analytical traceability.

CAS and Salt Form Clarification: CAS 159519-65-0 is the registry for the Enfuvirtide free peptide. The acetate salt form is assigned CAS 914454-00-5, with molecular formula C206H305N51O66 and molecular weight approximately 4551.93 g/mol. Many Chinese supplier listings use 159519-65-0 under the product name "Enfuvirtide Acetate," which conflates the free peptide and acetate salt registries. Knowlux declares the salt basis and acetate content per lot on the COA. Buyers should confirm whether the quoted material is free peptide or acetate salt before procurement, as the counter-ion shifts the mass balance by approximately 60 g/mol.

Sequence Verification Note: The 36-residue sequence is confirmed by KEGG, PeptideDB, and BEI Resources. The N-terminus is acetylated and the C-terminus is amidated. Enfuvirtide is derived from the HR2 region of gp41 and corresponds to the peptidic fusion inhibitor historically designated T-20 or DP178.

Product Parameters

Product Details

1. Overview

Enfuvirtide is a 36-residue synthetic peptide that binds to the heptad repeat 1 (HR1) region of the HIV-1 gp41 transmembrane glycoprotein, preventing the conformational transition required for viral envelope-cell membrane fusion. It was the first fusion inhibitor approved for clinical use (2003, marketed as Fuzeon) and remains a reference compound for studying HIV-1 entry mechanisms. The material supplied under this specification is research-grade and is not intended for human administration. Knowlux supplies this compound strictly for laboratory investigation of gp41-mediated fusion, peptide-protein interaction, and antiviral assay development.

2. Structural Profile

The peptide is linear and does not contain cysteine residues or disulfide bonds. Its N-terminus is acetylated and its C-terminus is amidated, blocking both termini against exopeptidase attack. The sequence is rich in hydrophobic and aromatic residues (Ile, Leu, Trp, Phe), which contribute to its interaction with the hydrophobic grooves of the gp41 HR1 trimer. The absence of disulfide constraints distinguishes Enfuvirtide from cyclic fusion inhibitors such as Eptifibatide, and its 36-residue length makes it one of the larger research peptides in routine supply. The peptide is derived from the HR2 region of gp41 (residues 127-162 of the gp41 ectodomain) and is thought to act by forming a six-helix bundle with HR1, sequestering the fusion-active intermediate.

3. Research Applications

Published pharmacological characterizations describe the following research applications:

• HIV-1 gp41-mediated fusion inhibition assays (cell-cell fusion and viral entry models)

• Peptide-protein interaction studies with HR1 and HR2 domains

• Antiviral resistance profiling against Enfuvirtide-sensitive and -resistant HIV-1 strains

• Reference standard development for HPLC and LC-MS analytical methods

Reported in vitro potency varies by assay system: Selleck reports IC50 values of 13.63 nM (HIV-1 IIIB in MT-2 cells) and 30.21 nM (HIV-1 Bal in M7 cells), while PeptideDB cites an IC50 of 23 +/- 6 nM in a cell-cell fusion assay. These values are assay-dependent and are provided for scientific reference only. They do not constitute clinical guidance or dosing recommendations.

Quality Control

Solubility and Handling

Solubility: Enfuvirtide solubility is highly matrix- and condition-dependent, and supplier data diverge substantially. Selleck reports water solubility of 100 mg/mL and DMSO solubility of 100 mg/mL (22.26 mM) for its Enfuvirtide Acetate lot. In contrast, ChemicalBook lists DMSO 5 mg/mL, DMF 5 mg/mL, and PBS (pH 7.2) 2 mg/mL for the CAS 159519-65-0 material. BEI Resources states that the lyophilized powder is insoluble in water and recommends dissolution in alkaline conditions such as sterile pyrogen-free 0.1% NaOH or 1% Na2CO3 at 0.1-1 mg/mL. One Chinese supplier states that the compound is essentially insoluble in pure water but reaches 82-142 mg/mL in pH 7.5 buffer. These discrepancies likely reflect differences in salt form, lot history, and buffer composition. For research use, alkaline aqueous conditions or DMSO should be evaluated on the specific lot; do not assume a single reported solubility value will apply across matrices. Prepare solutions fresh and avoid repeated freeze-thaw cycles.

Handling Precautions: Use powder-handling containment (glove box or fume hood with particulate control). Avoid inhalation of fine powder. Wear nitrile gloves, lab coat, and eye protection. ChemicalBook assigns GHS07 (warning, H315-H319-H335) for the CAS 159519-65-0 material; consult the lot-specific MSDS for applicable handling guidance.

Storage and Stability

Documentation Support

Per lot: COA, MSDS, certificate of origin, HPLC chromatogram, and mass spectrometry data. Sequence verification and counter-ion specification available on request. Custom specifications and third-party inspection can be arranged on a project basis.

About Knowlux

Knowlux Biotechnology is a GMP-oriented manufacturer and supplier of peptides, APIs and fine-chemical research compounds, operating from Hubei, China. We serve research groups, CDMOs and distributors in more than 40 countries, and support contract synthesis, custom packaging and technical documentation requests.

Compliance Statement

FOR RESEARCH USE ONLY. NOT FOR HUMAN USE. NOT FOR DIAGNOSTIC OR THERAPEUTIC USE.

This product is supplied for laboratory research use only. It is not for human or animal administration, not for diagnostic or therapeutic use, not for retail sale, and not for personal use. Enfuvirtide is an approved medicinal product in certain jurisdictions for specific clinical indications; however, the material offered under this specification is research-grade and is not intended for clinical use. The purchaser is responsible for verifying product specifications against their specific research requirements and for compliance with all applicable institutional, local, and national regulations governing research chemical acquisition, storage, and use. Research context statements are for scientific reference only and do not constitute medical advice, promotional claims, or dosing guidance.

Data Verification Notes: The molecular formula C204H301N51O64 and molecular weight 4491.88 g/mol for the free peptide are consistent across KEGG, PeptideDB, BEI Resources, and ChemicalBook. The acetate salt CAS is 914454-00-5, with formula C206H305N51O66 and molecular weight 4551.93, confirmed by InvivoChem, MedChemExpress, and PeptideDB. Supplier listings that apply CAS 159519-65-0 to the acetate salt form are technically imprecise; the free peptide and acetate salt have distinct registries. The solubility divergence across sources is noted in the Solubility section rather than reconciled into a single value, because the underlying measurements were made under different conditions and on different salt forms.

Formatting Note: All formulas, sequences, and comparison operators use plain ASCII notation to prevent character corruption on the platform. Section headings, table alignment, and spacing follow the approved product detail pattern. No trailing spaces or non-breaking characters are used; tables use consistent pipe alignment.