Melanotan Peptides: Research Overview
Melanotan I (MT-I) and Melanotan II (MT-II) are synthetic analogs of alpha-melanocyte-stimulating hormone (α-MSH). They were originally developed at the University of Arizona in the 1980s and have become important tools in melanocortin receptor research.
Peptide Profiles
Melanotan I (Afamelanotide)
| Property | Details |
|---|---|
| Type | Linear α-MSH analog |
| Amino Acids | 13 |
| Sequence | Ac-Ser-Tyr-Ser-Nle-Glu-His-D-Phe-Arg-Trp-Gly-Lys-Pro-Val-NH₂ |
| Primary Target | MC1R |
| Molecular Weight | ~1646 g/mol |
Melanotan II
| Property | Details |
|---|---|
| Type | Cyclic α-MSH analog |
| Amino Acids | 7 |
| Sequence | Ac-Nle-c[Asp-His-D-Phe-Arg-Trp-Lys]-NH₂ |
| Targets | MC1R, MC3R, MC4R, MC5R |
| Molecular Weight | ~1024 g/mol |
The Melanocortin System
Melanocortin Receptors
There are five known melanocortin receptors:
| Receptor | Location | Functions |
|---|---|---|
| MC1R | Skin, immune cells | Melanogenesis, inflammation |
| MC2R | Adrenal cortex | Cortisol production |
| MC3R | Brain, gut | Energy homeostasis |
| MC4R | Brain | Appetite, metabolism |
| MC5R | Exocrine glands | Sebum production |
Natural Ligands
Key Structural Differences
MT-I
MT-II
The cyclic structure of MT-II provides:
Research Applications
Melanogenesis Research
Receptor Pharmacology
Neuroscience
Comparative Studies
Reconstitution Protocol
Standard Volumes
| Peptide | Vial Size | BAC Water | Concentration |
|---|---|---|---|
| MT-I | 10mg | 2ml | 5mg/ml |
| MT-II | 10mg | 2ml | 5mg/ml |
Procedure
Storage Guidelines
Lyophilized
| Storage | Temperature | Duration |
|---|---|---|
| Long-term | -20°C | 2+ years |
| Short-term | 2-8°C | 6-12 months |
Reconstituted
Physical Properties
Appearance
Lyophilized:
Reconstituted:
Stability Notes
Research Considerations
Receptor Selectivity
When designing experiments:
| Research Focus | Consider |
|---|---|
| MC1R-specific | MT-I preferred |
| Pan-MC activity | MT-II appropriate |
| MC4R research | MT-II with controls |
Appropriate Controls
Quality Verification
Acceptable
Signs of Degradation
Related Research Compounds
| Compound | Notes |
|---|---|
| α-MSH | Natural ligand |
| ACTH (1-24) | Related peptide |
| SHU9119 | MC antagonist |
| Bremelanotide | MT-II derivative |
Conclusion
Melanotan peptides provide valuable research tools for studying the melanocortin system. MT-I's MC1R selectivity and MT-II's broader activity profile allow researchers to investigate different aspects of melanocortin biology.
*Melanotan peptides are sold for research purposes only and are not approved for human use.*
Frequently Asked Questions
What's the difference between Melanotan I and II?
MT-I is a linear 13-amino acid peptide that's more selective for MC1R. MT-II is a cyclic 7-amino acid peptide that binds multiple melanocortin receptors (MC1R, MC3R, MC4R, MC5R). MT-II's cyclic structure makes it more stable.
Why is Melanotan II cyclic?
The cyclic structure (lactam bridge) was designed to increase stability and resistance to enzymatic degradation. It also affects receptor selectivity, giving MT-II a broader activity profile than linear analogs.
Are Melanotan peptides light-sensitive?
Yes, both MT-I and MT-II should be protected from light, especially reconstituted solutions. Store in original vials away from direct light, and consider wrapping in foil for extra protection.
Need Help with Dosing?
Use our calculator to determine exact amounts for your research.
Peptide Calculator