MT1 (MT-1) usually denotes Melanotan I, now known as afamelanotide: a 13-residue analogue of alpha-melanocyte-stimulating hormone (α-MSH). Because “MT1” can also be read as a melatonin-receptor abbreviation, the full peptide name and sequence should appear in every protocol.
What Are the Key MT1 Research Specifications?
| Specification | Research record |
|---|---|
| Compound | MT1 |
| Category | misc |
| Listed purity | >99% |
| Molecular weight | 1646.8 g/mol for afamelanotide |
| Intended use | Laboratory research only |
What is the structure of Melanotan I?
Afamelanotide is [Nle4,D-Phe7]-α-MSH, with norleucine replacing Met4 and D-phenylalanine replacing L-Phe7. PubChem reports formula C78H111N21O19 and molecular mass 1646.8 g/mol. It is a linear, N-acetylated and C-amidated 13-mer, not an unspecified ~1.0 kDa peptide.
The analogue was synthesized in 1980 during α-MSH structure–activity work. The two substitutions increased potency and resistance to serum degradation relative to the endogenous hormone.
How does afamelanotide signal?
Afamelanotide is a melanocortin-receptor agonist with strong activity at MC1R, a Gs-coupled receptor that raises cAMP and drives melanogenic transcription in melanocytes. It is not universally selective across all melanocortin receptors, so effects in cells expressing MC3R, MC4R or MC5R require receptor-level attribution.
Which controls improve melanocortin experiments?
Report receptor expression and species. Include α-MSH as a physiological comparator, a receptor antagonist or knockout, and vehicle. Measure cAMP or a proximal reporter before interpreting pigmentation, tyrosinase or transcriptional changes. Because D-Phe7 changes proteolytic stability, exposure-matched time courses are more informative than a single nominal concentration.
How should Melanotan I be handled?
Confirm the Nle4 and D-Phe7 substitutions, N-acetylation, C-terminal amidation, counterion and intact mass. Diastereomeric impurities may not be resolved by a generic purity statement. Use low-binding consumables, single-use aliquots and a lot-qualified buffer. Protect solutions from repeated freeze-thaw and establish stability in the actual light, temperature and matrix conditions used by the assay.
Which Sources Support MT1 Research?
- Sawyer et al., synthesis and prolonged activity of [Nle4,D-Phe7]-α-MSH, PNAS (1980), DOI: 10.1073/pnas.77.10.5754.
- Yu et al., receptor structures with α-MSH and afamelanotide, Cell Research (2021), PMID 34433901.
How Can MT1 Results Be Interpreted Without Overclaiming?
The strongest MT1 evidence connects identity to mechanism to phenotype in that order. For MT1, chemical identity, target engagement and downstream phenotype are separate layers. A change in migration, viability or gene expression does not by itself prove the proposed molecular target. A useful study includes an orthogonal analytical identity check, a target-dependent perturbation and a second assay that measures the same biology by a different method. This design makes a positive result easier to reproduce and a negative result easier to interpret.
For citation-ready MT1 reporting, provide raw concentration units, biological replicate counts, prespecified exclusions and the exact time point. Separate exploratory endpoints from confirmatory ones. If exposure was not measured, describe potency as nominal rather than intracellular or free concentration. Limit the conclusion to the model used; avoid converting a pathway observation into a claim about clinical benefit.
Is MT1 for Research Use Only?
Melanotan I is supplied for laboratory research only. It is not for human or veterinary use.
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What Are Common Questions About MT1?
What is MT1?
MT1 (MT-1) usually denotes Melanotan I, now known as afamelanotide: a 13-residue analogue of alpha-melanocyte-stimulating hormone (α-MSH). Because “MT1” can also be read as a melatonin-receptor abbreviation, the full peptide name and sequence should appear in every protocol.
How should researchers verify MT1?
Confirm the exact molecular form on the lot certificate and pair chromatographic purity with an orthogonal identity method such as mass spectrometry or NMR. Use the molecular weight, counterion and content stated for that verified form when calculating molarity.
Is MT1 intended for human use?
MT1 is listed for controlled laboratory research only. It is not intended for human or veterinary use.