Dihexa Molecular Weight, Sequence & CAS Reference

Chemical Identification and CAS Reference

Dihexa is an oligopeptide derivative synthesized primarily for laboratory investigation into hepatocyte growth factor (HGF) and c-Met receptor interactions. Unlike unmodified linear peptides, Dihexa incorporates an N-terminal fatty acid acyl modification (hexanoyl chain) linked to an oligopeptidic core derived from the hexapeptide fragment of angiotensin IV (Ang IV). Its primary scientific designation is N-hexanoyl-Tyr-Ile-6-aminohexanoic acid-His-Phe-NH2.

The Chemical Abstracts Service (CAS) registry identifier assigned to the Dihexa free base is 1401708-83-5. In published preclinical literature, the molecule is occasionally referenced under internal development codes such as PNB-0408. Precise chemical nomenclature, canonical SMILES string representations, and systematic IUPAC definitions must be validated against third-party analytical documentation prior to deploying the material in enzymatic or cellular binding models. Researchers cross-referencing catalog standards can review complete molecular data across our full all-peptides inventory.

Molecular Weight, Formula, and Mass Spectrometry Standard

The molecular formula of Dihexa free base is C44H64N8O8, corresponding to a theoretical monoisotopic mass of 856.4847 Da and a nominal molecular weight of approximately 857.05 g/mol. When calculating molarity for high-throughput in vitro binding assays, investigators must distinguish between the theoretical exact mass of the free base and the total formula weight of the synthesized salt form.

Characterization via Electrospray Ionization Mass Spectrometry (ESI-MS) typically demonstrates a predominant protonated molecular ion peak at [M+H]+ = 857.5 m/z, alongside secondary doubly charged species [M+2H]2+ = 429.3 m/z depending on ionization polarity and matrix conditions. Any observed deviation greater than ±0.5 Da from the theoretical molecular weight warrants structural verification via high-resolution tandem mass spectrometry (MS/MS) to ensure sequence integrity and identify potential truncated synthetic impurities.

Amino Acid Sequence and Structural Modification

The primary amino acid sequence of Dihexa features both standard L-amino acids and non-proteinogenic amino acid residues designed to modify conformational flexibility and enzymatic susceptibility. The defined sequence structure is represented as follows:

Hexanoyl-L-Tyrosyl-L-Isoleucyl-6-Aminohexanoyl-L-Histidyl-L-Phenylalaninamide

The inclusion of 6-aminohexanoic acid (also known as 6-Ahx or ε-aminocaproic acid) serves as an unnatural hydrophobic spacer between the L-Isoleucine and L-Histidine residues. Furthermore, the C-terminus is modified with a terminal carboxamide group (-NH2) rather than a free carboxylic acid (-COOH), while the N-terminus is capped with a six-carbon hexanoyl moiety. These specific structural end-caps alter the overall dipole moment, logP partition coefficient, and steric profile compared to native angiotensin fragments studied in receptor-binding models.

Salt Counter-Ions and Net Peptide Content Determination

Solid-phase peptide synthesis (SPPS) and subsequent reverse-phase high-performance liquid chromatography (RP-HPLC) purification yield Dihexa as a salt, typically containing either trifluoroacetate (TFA) or acetate counter-ions bound to basic functional groups (such as the imidazole nitrogen of Histidine). Consequently, the total mass of a lyophilized vial consists of three components: pure target peptide, bound salt counter-ions, and residual non-stoichiometric moisture.

Researchers must account for the net peptide content (NPC) when preparing molar stock solutions. Net peptide content typically ranges from 70% to 85% in standard TFA salt preparations. For example, a 10.0 mg vial of lyophilized Dihexa salt with an analytical NPC of 80.0% contains precisely 8.0 mg of active Dihexa free base (equivalent to approximately 9.33 micromoles). Reconstitution without adjusting for the salt factor results in systematic under-dosing in quantitative cellular assays. Accurate mass-to-volume conversions can be executed using our laboratory reconstitution-calculator.

Physicochemical Properties and Solubilization Limits

Dihexa exhibits a calculated logP of approximately 3.2 to 3.8, reflecting significant lipophilicity imparted by the N-terminal hexanoyl group, the hydrophobic amino acid side chains (Ile, Phe), and the Ahx spacer. Because of this hydrophobic character, direct dissolution of Dihexa free base or TFA salt in unbuffered aqueous solutions (pH 7.4) often yields incomplete solubilization or micro-precipitation at concentrations exceeding 1.0 mg/mL.

To achieve stable homogenous stock solutions for laboratory protocols, it is recommended to pre-solubilize the compound in organic solvents such as dimethyl sulfoxide (DMSO) or ethanol before diluting into aqueous assay buffers. Stock solutions prepared in high-purity DMSO can reach concentrations of 10–20 mg/mL. When diluting into culture media or physiological saline, the final organic solvent concentration should be maintained below 0.1% to 0.5% v/v to eliminate solvent-induced cytotoxicity or buffer interference in cell culture models.

Analytical Quality Assurance: HPLC, MS, and Endotoxin Testing

To guarantee experimental reproducibility, every lot of Dihexa produced for PX1 Research undergoes rigorous verification within ISO 17025 accredited analytical facilities using standardized HPLC and Mass Spectrometry protocols. Chromatographic purity is established using analytical RP-HPLC with gradient elution (water/acetonitrile containing 0.1% TFA) across a C18 stationary phase, requiring a minimum purity threshold of ≥98.0% by peak area integration at 214 nm and 280 nm.

In addition to chromatographic purity and mass identity, quantitative testing includes bacterial endotoxin quantification via the Limulus Amebocyte Lysate (LAL) assay, ensuring levels remain well below established limits (<0.01 EU/μg) for sensitive in vitro biological systems. Lot-specific certificates showing raw HPLC chromatograms, mass spectra, and moisture content analysis can be retrieved directly via our public coa portal.

Comparative Structural Analysis of Research Oligopeptides

In preclinical neuro-biological research, scientists frequently evaluate multiple modified peptides side-by-side to compare receptor affinity, metabolic stability, and signaling cascade activation. Dihexa represents a heavily modified, lipophilic hexapeptide derivative targeting HGF/c-Met pathways. In contrast, other structurally distinct small peptides utilized in central nervous system models include heptapeptide derivatives and synthetic neurotrophic fragments.

For example, researchers studying structural stability and N-terminal modifications often compare Dihexa with semax-sequence-structure, an N-acetylated ACTH(4-10) analog (Met-Glu-His-Phe-Pro-Gly-Pro), and selank-molecular-weight, a synthetic tuftsin derivative (Thr-Lys-Pro-Arg-Pro-Gly-Pro). Furthermore, synthetic mimetic models often incorporate compounds such as p21-peptide-specs, a CNTF-derived peptide derivative. Understanding how terminal capping (such as hexanoylation versus acetylation) and sequence length influence solubility, charge density, and enzymatic cleavage rates is critical when designing comparative in vitro screening assays.

Handling, Reconstitution, and Storage Specifications

Lyophilized Dihexa powder demonstrates high physical and chemical stability when stored under controlled environment conditions. For long-term preservation, sealed vials should be kept at -20°C or -80°C in a desiccated cabinet, protected from light exposure. Under these storage parameters, the dry peptide remains stable for up to 24 months without significant degradation or oxidation of sensitive residues like Histidine or Tyrosine.

Upon reconstitution with sterile DMSO or compatible laboratory solvents, aliquots should be divided into single-use working volumes to avoid repeated freeze-thaw cycles, which accelerate molecular aggregation and physical cleavage. Reconstituted liquid aliquots stored at -20°C should be utilized within 30 to 60 days. Laboratory researchers requiring larger quantities or customized batch sizes for high-throughput screening projects can explore tailored ordering options through our wholesale institutional portal.

In Vitro Research Applications and Mechanistic Targets

In published preclinical literature, Dihexa has been investigated as a potent small-molecule agonist that facilitates dimerization and autophosphorylation of the c-Met receptor tyrosine kinase upon binding to Hepatocyte Growth Factor (HGF). In vitro binding assays demonstrate that Dihexa binds to immobilized HGF with high affinity (pico- to nanomolar equilibrium dissociation constants reported in cell-free systems).

Ex vivo neuronal culture models utilize Dihexa to investigate dendritic arborization, spinogenesis, and synaptogenesis pathways mediated by downstream intracellular cascades, including the MAPK/ERK and PI3K/Akt signaling routes. All experimental procedures involving Dihexa must be conducted exclusively in vitro or in established animal tissue models under strict laboratory containment standards; human or veterinary administration is strictly prohibited.

PX1 Research Sourcing and Supply Integrity

PX1 Research supplies USA-manufactured research peptides designed specifically to meet the rigorous demands of institutional laboratories, academic research centers, and private biotechnology facilities. Every synthesis batch of Dihexa undergoes comprehensive quality control inside ISO 17025 compliant laboratories, utilizing multi-angle light scattering, RP-HPLC, and ESI-MS to confirm purity, stoichiometry, and salt identity.

By adhering to strict cGMP-compliant manufacturing practices and providing transparent lot-level reporting, PX1 Research eliminates chemical variability across study cohorts. Researchers evaluating specialized solid or encapsulated analytical standards for material characterization can view product options such as dihexa-capsules-10mg directly within our catalog. Orders ship directly from our centralized facilities in California and Arizona with same-day dispatch for orders finalized Monday through Friday.