MELANOTAN II 10 mg

One Peptides Melanotan II 10 mg – chemical reagent for laboratory tests

Melanotan – Research Use Only (RUO). Chemical reagent intended only for laboratory tests. It is not intended for human consumption or diagnostic purposes.
Related categories and reagents: In the context of this area of ​​research, it is also worth comparing GHK-Cu copper peptide and Epithalon anti-aging peptide.

Melanotan II vs GHK-Cu and Epithalon. They are sometimes grouped as “short peptides,” but the mechanisms described in the literature are distinct. Melanotan II (1,024.18 g/mol) is a cyclic heptapeptide—an α-MSH analogue described as a nonselective agonist of the melanocortin receptors MC1R, MC3R, MC4R and MC5R. GHK-Cu (approximately 403 g/mol with Cu²⁺) is not a ligand of melanocortin receptors; its research identity is a tripeptide-copper complex. Epithalon (390.35 g/mol) is a tetrapeptide without a metal ion and without described affinity for MC receptors. Only the chemical class is shared, not the molecular target, and the mass difference (1,024 versus 390–403 g/mol) reflects two different orders of molecular size.

Introduction and research framework

Melanotan II (MT-II) is a synthetic cyclic heptapeptide that is an analogue of the naturally occurring hormone α-melanotropin (α-MSH – α-Melanocyte Stimulating Hormone). The peptide was developed at the University of Arizona in the 1980s by a team led by Dr. Victor Hruby as a tool for research on melanocortin receptors.

Melanotan II is characterized by a cyclic structure, which gives it increased metabolic stability compared to linear α-MSH. As a non-selective agonist of melanocortin receptors (MCR), this peptide is used in scientific research on the signaling pathways and functions of individual MC1R-MC5R subtypes.

General characteristics of the melanotan II compound

Melanotan II is a cyclic peptide with the sequence Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-NH2, designed as a stable analogue of α-MSH. Cyclization through the lactone bond between Asp and Lys and the presence of D-phenylalanine increase resistance to enzymatic degradation.

In the context of scientific research, Melanotan II serves as:

• Non-selective agonist of melanocortin receptors
• MC1R-MC5R pathway research tool
• Structural model for the design of selective ligands
• The standard in melanocortin research

The One Peptides Melanotan II 10 mg material is supplied in the form of a high-purity freeze-dried powder intended for use in biochemical and pharmacological research.

What is Melanotan II?

MT II is a synthetic analogue of α-MSH, designed to increase stability and potency compared to the natural hormone. α-MSH is a product of post-translational processing of proopiomelanocortin (POMC) and acts through melanocortin receptors (MCR).

History of Development

Comparison with α-MSH

Melanocortin family

Structure and physicochemical properties

Sequence and Structure

Melanotan II is a cyclic heptapeptide:

Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-NH2

Where:

• Ac – acetyl group at the N-terminus
• Nle – norleucine (replaces Met with α-MSH)
• cyclo[Asp…Lys] – cyclization by amide bond between side chains
• D-Phe – D-phenylalanine (increases stability)
• NH2 – C-terminal amidation

Characteristics of Amino Acids

• Position 1 (Nle) – norleucine, replaces methionine (avoids oxidation)
• Position 2 (Asp) – aspartic acid, participates in cyclization
• Position 3 (His) – histidine, part of the pharmacophore core
• Position 4 (D-Phe) – D-phenylalanine, part of the core (D configuration!)
• Position 5 (Arg) – arginine, part of the pharmacophore core
• Position 6 (Trp) – tryptophan, part of the pharmacophore core
• Position 7 (Lys) – lysine, participates in cyclization

Pharmacophore Core

The His-Phe-Arg-Trp sequence constitutes the core pharmacophore of melanocortins, conserved in Melanotan II (as His-D-Phe-Arg-Trp).

Physicochemical properties

Comparison with Melanotan I

Purity, identification and quality control

Product Specification ONE Melanotan II 10 mg

Quality parameters:

Storage and laboratory handling

Storage Conditions

Freeze-dried form:
– Temperature: -20°C (optimal)
– Permissible: 2-8°C (up to 1 month)
– Protect from light (tryptophan)
– Protect against moisture
– Shelf life: 24 months at -20°C

After reconstitution:
– Solvent: sterile water or bacteriostatic water
– Storage: 2-8°C in the dark
– Use within 14-21 days
– Freezing aliquots recommended

Reconstitution Instructions

1. Equalize the temperature of the vial (15-20 min)
2. Add sterile water slowly along the side
3. Recommended concentration: 1-2 mg/ml
4. Mix gently by turning
5. The solution should be clear
6. Protect from light

Stability

The cyclic structure of Melanotan II provides:

• Increased resistance to proteases
• Longer stability in solution than α-MSH
• Oxidation protection (Nle instead of Met)

Mechanism of action at the molecular level

Melanocortin receptors

Melanotan II is a non-selective agonist of melanocortin receptors (MCR), Gs-protein coupled GPCRs:

Receptor affinity (in vitro):

Intracellular Signaling

In cell culture studies:

• Activation of adenylase cyclase
• Increase in cAMP levels
• PKA activation
• CREB phosphorylation

Comparative Research

Melanotan II is compared with:

• α-MSH (endogenous ligand)
• Melanotan I (selective MC1R)
• Bremelanotide (PT-141, MT-II analogue)
• Setmelanotide (selective MC4R)

Pharmacophore Core

The His-D-Phe-Arg-Trp sequence is essential for activity. Structure-activity studies showed:

• His crucial for binding
• D-Phe increases stability and potency
• Arg and Trp necessary for activation

Applications in Scientific Research

Receptor Research

• Characterization of MC1R-MC5R receptors
• Binding and activation studies
• Selectivity and specificity
• Desensitization and internalization

Signaling Research

• cAMP/PKA/CREB pathways
• Crosstalk with other GPCRs
• Mechanisms of regulation of gene expression
• Transcription modulation

Structure-Activity Research

• Optimization of receptor selectivity
• The role of cyclization in stability
• The importance of individual amino acids
• Designing new analogues

Melanocyte Biology (In Vitro)

• Mechanisms of melanogenesis
• Tyrosinase regulation
• Signaling pathways in melanocytes
• Interactions with other factors

Neurobiology

• MCR expression in the CNS
• MC3R and MC4R functions
• Research models for MC4R

Reservations

IMPORTANT: The product is intended for in vitro testing only. Not intended for:
– Use in humans or animals
– Cosmetic or therapeutic purposes
– Any clinical use

Summary

Melanotan II is a cyclic synthetic analog of α-MSH, characterized by non-selective agonism towards MC1R-MC5R melanocortin receptors. Its stable cyclic structure and well-understood pharmacological properties make it a valuable tool in research on the melanocortin system.

Material One Peptides Melanotan II 10 mg offers:

• High purity ≥98% HPLC
• Confirmed cyclic structure
• Stable freeze-dried form
• Certificate of analysis for each batch

Science FAQ

1. What is Melanotan II and what is its structure?

Melanotan II (MT-II) is a synthetic cyclic heptapeptide with the sequence Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-NH2 and a molar mass of 1024.18 g/mol. It is an analogue of α-MSH with a cyclic structure ensuring increased stability. It acts as a non-selective agonist of melanocortin receptors (MC1R-MC5R). The CAS number is 121062-08-6.

2. What is the difference between Melanotan II and Melanotan I?

Melanotan I (Afamelanotide) is a linear 13 AA peptide that is more selective for MC1R. Melanotan II is a cyclic heptapeptide, non-selective for MC1R-MC5R. MT-II has a smaller mass (~1024 vs. ~1646 Da) and has activity on a broader spectrum of receptors, including MC3R and MC4R in the CNS.

3. Why does Melanotan II contain norleucine instead of methionine?

Norleucine (Nle) replaces methionine (Met) present in natural α-MSH to avoid oxidation of the thioether group of methionine. Oxidized methionine (sulfoxide) loses its biological activity. Norleucine has similar hydrophobic properties but is stable to oxidation.

4. What does “cyclic” mean in the context of a peptide structure?

The cyclic structure of Melanotan II is formed by the formation of an amide bond between the aspartic acid side chain (Asp) and the lysine side chain (Lys). This cyclization creates a ring that stiffens the conformation of the peptide and increases its resistance to degradation by proteases.

5. What research is Melanotan II used for?

MT II is used in in vitro studies on: melanocortin receptors (MC1R-MC5R), cAMP/PKA signaling pathways, the mechanics of melanogenesis, and as a standard in melanocortin structure-activity studies. It is not intended for use on humans or animals.

The most important research conclusions

The most important features of the ONE Melanotan II 10 mg product:

• Type – cyclic α-MSH analogue
• Sequence – Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-NH2
• Molar mass – 1024.18 g/mol
• CAS number – 121062-08-6
• Receptors – MC1R-MC5R (non-selective)
• Structure – cyclic (Asp-Lys lactone)
• Cleanliness – minimum 98% HPLC
• Form – lyophilisate (white powder)
• Destiny – only in vitro tests