Dynorphin A (1-13) Acetate | CAS 72957-38-1 | Kappa Opioid Receptor Agonist (Research Use Only) | Knowlux
Product Description
Dynorphin A (1-13) Acetate, CAS 72957-38-1, is a synthetic 13-amino-acid peptide corresponding to the N-terminal fragment of the endogenous opioid peptide dynorphin A, supplied by Knowlux for laboratory research use. The sequence is H-Tyr-Gly-Gly-Phe-Leu-Arg-Arg-Ile-Arg-Pro-Lys-Leu-Lys-OH, a linear peptide with a free N-terminal tyrosine and a free C-terminal lysine carboxylate. The free peptide molecular formula is C75H126N24O15 and the molecular weight is 1603.96 g/mol. The acetate salt corresponds to C77H130N24O17 with a molecular weight of approximately 1664.04 g/mol on a monoacetate basis. Each lot is released with a lot-specific COA, MSDS and analytical traceability.
CAS and Salt Form Clarification: CAS 72957-38-1 presents a salt-form documentation ambiguity common to several peptide APIs in this catalogue. The CAS is most consistently paired with the free peptide formula C75H126N24O15 and MW 1603.96 across ChemicalBook, Adooq, Biosynth, Catorm, and the majority of Chinese supplier listings, yet the product name in those same listings is frequently rendered as Dynorphin A (1-13) Acetate. A separate catalogue cluster (Aobious, Biorbyt, BOC Sciences, CymitQuimica, BenchChem) lists Porcine dynorphin A (1-13) acetate under CAS 72957-38-1 with the monoacetate formula C77H130N24O17 and MW 1664, which is the chemically coherent monoacetate assignment (1603.96 + 60.05 = 1664.01). The practical reading is that 72957-38-1 identifies the compound family, while the molecular formula and molecular weight declared on the lot COA determine whether the material is free peptide or monoacetate. Knowlux specifies the salt basis, acetate content, and water content per lot on the COA. Buyers should confirm the declared formula and molecular weight (1603.96 versus 1664) before using the material in quantitative assays, as the 60 g/mol counter-ion difference is material for molarity calculations.
Structural Note: Dynorphin A (1-13) is the shortest fragment of dynorphin A that retains the full receptor-binding pharmacophore of the parent peptide. The N-terminal sequence Tyr-Gly-Gly-Phe (the opioid message domain) is the conserved signature of the endogenous opioid peptide family, while the C-terminal basic cluster Arg-Arg-Ile-Arg-Pro-Lys-Leu-Lys constitutes the address domain that confers kappa receptor selectivity. Unlike the disulfide-constrained peptides in the Linaclotide, Plecanatide, and Ziconotide families, Dynorphin A (1-13) is linear, contains no cysteine, and has no intramolecular cross-link, which simplifies handling with respect to reducing agents. The peptide contains no methionine and no tryptophan, giving it a favorable intrinsic oxidation profile; the sole aromatic residues are Tyr1 and Phe4.
Product Parameters
| Item | Specification |
|---|---|
| Product Name | Dynorphin A (1-13) Acetate |
| Synonyms | Dynorphin A (porcine) fragment 1-13; Dyn(1-13); YGGFLRRIRPKLK; H-Tyr-Gly-Gly-Phe-Leu-Arg-Arg-Ile-Arg-Pro-Lys-Leu-Lys-OH |
| CAS No. | 72957-38-1 (compound family; see CAS Clarification) |
| Molecular Formula | C75H126N24O15 (free peptide); C77H130N24O17 (monoacetate) |
| Molecular Weight | 1603.96 g/mol (free peptide); ~1664.04 g/mol (monoacetate) |
| Sequence (1-letter) | YGGFLRRIRPKLK |
| Sequence (3-letter) | H-Tyr-Gly-Gly-Phe-Leu-Arg-Arg-Ile-Arg-Pro-Lys-Leu-Lys-OH |
| Sequence Length | 13 amino acids, linear |
| Key Structural Features | N-terminal opioid message domain (Tyr-Gly-Gly-Phe); C-terminal basic address domain; no cysteine or disulfide; no methionine or tryptophan; free N-terminus; free C-terminal Lys-OH |
| InChIKey | OVVIBUHLQIYUEU-JASZZEBFNA-N |
| Appearance | White to off-white lyophilized powder |
| Solubility | Water: >=60 mg/mL (37.41 mM); DMSO: soluble; 50 mM sodium phosphate (pH 8.5) or 10% DMSO in PBS (pH 7.5) also reported |
| Purity | >=95.0% to >=98.0% (HPLC); supplier-dependent |
| Identity | Confirmed by LC-MS and HPLC |
| Grade | Research grade |
| Counter-ion | Acetate (lot-specific, declared on COA) |
| Acetate Content | 5.0% to 12.0% (supplier specification) |
| Peptide Content | >=80.0% (supplier specification) |
| Water Content | <=8.0% (supplier specification) |
| Single Impurity | <=2.0% (HPLC; <=1.0% available) |
| Storage | See Storage and Stability section |
| Packaging | 1 mg / 5 mg / 10 mg / 25 mg / 50 mg / 100 mg vial; bulk on request |
| Application | Laboratory research use only |
| Origin | China |
Product Details
1. Overview
Dynorphin A (1-13) is a 13-residue synthetic peptide corresponding to the N-terminal fragment of dynorphin A, an endogenous opioid peptide derived from the prodynorphin precursor. Dynorphin A was originally isolated from porcine pituitary and is widely distributed throughout the central nervous system, with particularly high concentrations in the spinal cord, hippocampus, and hypothalamus. The (1-13) fragment is the minimal sequence that retains high-affinity binding to the kappa opioid receptor (KOR), and it is the fragment most commonly used in pharmacological research because it balances receptor potency against synthetic accessibility. Dynorphin A (1-13) is a potent KOR agonist with antinociceptive activity at physiological concentrations, and it has been used extensively as a tool compound for studying kappa opioid pharmacology, pain processing, and the non-opioid neurotoxic actions of dynorphin peptides. The material supplied under this specification is research-grade and is not intended for human administration.
2. Receptor Pharmacology and Selectivity
Dynorphin A (1-13) binds the kappa opioid receptor with exceptionally high affinity, and it is the prototypical endogenous KOR agonist. The BindingDB curated dataset for this ligand-target pair contains multiple affinity constants from independent assays that illustrate both the potency of the interaction and the assay-dependent spread: Ki 0.31 nM and Ki 0.4 nM for binding to the cloned kappa receptor by competitive inhibition of [3H]diprenorphine; IC50 0.114 nM for inhibition of [3H]U-69593 binding to kappa receptors in guinea pig brain homogenate; and EC50 1.5 nM in a functional agonist assay. A separate report in the primary literature lists a Ki of 0.09 nM for displacement of [3H]U69,593 from human KOR expressed in mouse HN9.10 cell membranes, and a 2004 study in bovine adrenal medulla reported a Ki of 2.3 nM for inhibition of [3H]-EKC binding. The spread from approximately 0.09 nM to 2.3 nM reflects differences in receptor source, radioligand, and membrane preparation, with the sub-nanomolar values representing the high-affinity consensus for the cloned and native KOR. BenchChem pharmacology compilation characterizes the fragment as KOR-preferring, with high affinity at KOR and moderate affinity at MOR and DOR, and ChemicalBook biological activity entry describes Porcine dynorphin A (1-13) as a potent endogenous opioid receptor (kappa opioid receptor) agonist with analgesic activity at physiological concentrations.
Beyond its opioid receptor pharmacology, Dynorphin A (1-13) has a well-documented non-opioid neurotoxic profile that is important for interpreting in vitro results. ChemicalBook and Aobious both note that exposure to Dynorphin A (1-13) causes acute increases in intracellular calcium ([Ca2+]i) in individual neurons similar to those seen with acute NMDA treatment, and that continuous exposure (100 microM) produces neuronal loss. ChemicalBook specifically reports a significant loss in neuronal viability at 4 hours with visible destruction of neuronal morphology at 16 hours following exposure to 33 microM Dynorphin A (1-13). These non-opioid actions are distinct from KOR agonism and are relevant to any research design in which dynorphin is applied to neuronal cultures at micromolar concentrations. These values are assay- and system-dependent and are provided for scientific reference only.
3. Research Applications
Published pharmacological characterizations and documented protocols describe the following research applications:
-
Kappa opioid receptor (KOR) binding and functional agonist assays (radioligand displacement, GTPgammaS binding, calcium mobilization)
-
Antinociception and pain processing research models (spinal and supraspinal administration)
-
Opioid receptor selectivity profiling across KOR, MOR, and DOR
-
Non-opioid neurotoxicity and calcium dysregulation studies (NMDA-like [Ca2+]i increases, neuronal viability)
-
Neurolysin inhibition and dynorphin metabolism studies (Dynorphin A (1-13) as a neurolysin substrate/inhibitor)
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Cardiovascular regulation and brain protection research contexts
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Reference standard development for HPLC and LC-MS analytical methods
These descriptions are derived from published research and are provided for scientific reference only.
Quality Control
| Test Item | Method | Acceptance Criteria |
|---|---|---|
| Purity | RP-HPLC | >=95.0% (entry grade); >=96.0% (Phoenix Biotech); >=98.0% (reference standard, Adooq, Aobious) |
| Identity | LC-MS and HPLC | Consistent with structure (1603.96 +/- 1 for free peptide; 1664 +/- 1 for monoacetate) |
| Single Impurity | RP-HPLC | <=2.0% (<=1.0% available) |
| Peptide Content | Nitrogen analysis or AAA | >=80.0% (reference standard) |
| Acetate Content | HPLC or ion chromatography | 5.0% to 12.0% (reference standard) |
| Water Content | Karl Fischer | <=8.0% (reference standard) |
| Appearance | Visual | White to off-white powder |
Solubility and Handling
Solubility: Dynorphin A (1-13) is freely soluble in water and in DMSO, with aqueous solubility among the highest in this catalogue. ChemicalBook reports water solubility of >=60 mg/mL (37.41 mM). BenchChem documentation states that the reported solubility of Dynorphin A (1-13) in water ranges from 0.80 mg/mL to >=50 mg/mL depending on the study, and that DMSO is used for initial solubilization. Phoenix Biotech provides specific reconstitution guidance for a related Dynorphin A (1-13) product: soluble in 50 mM sodium phosphate buffer (pH 8.5) or in 10% DMSO in PBS buffer (pH 7.5). For practical stock preparation, water at >=60 mg/mL is the most consistently supported condition for the acetate salt; DMSO is a viable alternative for applications requiring anhydrous conditions or for lots with lower aqueous solubility. Phoenix Biotech recommends allowing the lyophilized powder to equilibrate to room temperature for 25-45 minutes before opening, brief vortexing to concentrate material at the bottom of the tube, and gentle inversion after adding the reconstitution solution. Prepare solutions fresh and aliquot to 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. Because the peptide contains no cysteine or methionine, reducing agents and oxidation-protection measures are not required. The principal handling consideration is the hygroscopic nature of the lyophilized powder; equilibrate vials to room temperature before opening to prevent condensation.
Storage and Stability
| Format | Temperature | Shelf Life |
|---|---|---|
| Lyophilized Powder | -20C, sealed, desiccated, inert atmosphere | 12 months (ProbeChem); recommended long-term condition (ChemicalBook, Aobious) |
| Lyophilized Powder | 0C to 5C, dry | Recommended by Phoenix Biotech for dry peptide storage |
| Lyophilized Powder | 4C, sealed | 6 months (ProbeChem); short-term only (USBio) |
| Reconstituted Solution | -80C, aliquoted | 6 months (typical for research peptides) |
| Reconstituted Solution | -20C, aliquoted | 1 month (typical for research peptides) |
Documentation Support
Per lot: COA, MSDS, HPLC chromatogram, and mass spectrometry data. Acetate content, water content, peptide content, and salt-form stoichiometry 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. Dynorphin A (1-13) Acetate is not approved as a medicinal product in any jurisdiction. 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 free peptide molecular formula C75H126N24O15 and molecular weight 1603.96 are confirmed by ChemicalBook (CAS 72957-38-1), Adooq, Biosynth, Catorm, and BenchChem. The monoacetate formula C77H130N24O17 and MW 1664 are confirmed by Aobious, Biorbyt, BOC Sciences, CymitQuimica, and BenchChem. The sequence H-Tyr-Gly-Gly-Phe-Leu-Arg-Arg-Ile-Arg-Pro-Lys-Leu-Lys-OH is confirmed across ChemicalBook, Adooq, Phoenix Biotech, Biosynth, and Catorm. The BindingDB affinity constants (Ki 0.31 nM; Ki 0.4 nM; IC50 0.114 nM; EC50 1.5 nM) are from the BindingDB BDBM224024 entry. The primary literature Ki values (0.09 nM for human KOR; 2.3 nM for bovine adrenal medulla) are from the PMC table and the ScienceDirect abstract, respectively. The KOR-preferring selectivity characterization is from BenchChem and ChemicalBook. The non-opioid neurotoxicity data (33 microM, 4 h viability loss; 16 h morphological destruction; 100 microM continuous exposure; NMDA-like [Ca2+]i increases) are from ChemicalBook and Aobious. Solubility values are reported with their source conditions rather than reconciled into a single figure because the ChemicalBook >=60 mg/mL water value, the BenchChem 0.80-50 mg/mL range, and the Phoenix Biotech buffer-specific guidance reflect different measurement contexts and peptide lots. Storage guidance divergence (-20C versus 0-5C) is reported as-is; the -20C powder condition is the most widely supported archival temperature.
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.
