MT2 specifications and molecular characteristics
The technical specification for Melanotan II, the MT2 research material supplied by MT2 Labs: molecular formula C50H69N15O9, average molecular weight 1024.18 g/mol, 7 residues, supplied as a white lyophilized powder. Each item is explained below.
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Specification table
| Product | Melanotan II |
|---|---|
| Type | Synthetic cyclic α-MSH analog (7 residues) |
| Molecular formula | C50H69N15O9 |
| Molecular weight | 1024.18 g/mol (average) |
| Length | 7 residues |
| Sequence | Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-NH2 |
| Cyclization | Lactam, Asp2–Lys7 side chains |
| N-terminus | Acetyl-norleucine |
| C-terminus | Amide (Lys7-NH2) |
| CAS number | 121062-08-6 |
| Receptor design | Melanocortin receptors MC1R, MC3R, MC4R and MC5R |
| Form | White lyophilized powder |
| Vial sizes | 10 mg |
| Purity specification | ≥95% (HPLC-UV) |
| Purity, current lots | 99.90% |
| Identity specification | Confirmed by LC-MS |
| Testing laboratory | Freedom Diagnostics (independent) |
| Storage | Store sealed, dry and protected from light at the temperature stated on the vial label. Allow a cold vial to reach room temperature before opening. |
| Designation | Research use only |
Current lot results against specification
Every current lot meets the release specification. Current lots test at 99.90% by HPLC-UV against a specification of ≥95%, and identity is confirmed by LC-MS on every lot.
MT2 molecular formula
The molecular formula of Melanotan II is C50H69N15O9. Includes the N-terminal acetyl group, the C-terminal amide and the Asp–Lys lactam bridge.
MT2 molecular weight
The average molecular weight of Melanotan II is 1024.18 g/mol. "Average" means it is calculated from natural isotope abundances, which is the value used to predict the ions seen in LC-MS. With this weight, Melanotan II is expected at m/z 1025.2 with one charge and m/z 513.1 with two charges.
MT2 sequence
Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-NH2
Residues inside the brackets form the lactam ring (Asp2 side chain to Lys7 side chain).
Structure and modifications
MT2 is Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-NH2. The cyclizing amide bond between Asp2 and Lys7 side chains removes one water from the linear sequence, which is reflected in the formula. The N-terminus is acetylated and the C-terminus amidated, so the molecule has no free terminal charges; arginine is its main basic group.
Receptor classification
Melanotan II is designed for activity at the melanocortin receptors MC1R, MC3R, MC4R and MC5R.
Physical form
White lyophilized powder, recorded as the appearance on every certificate. Lyophilization (freeze-drying) removes water, which slows most chemical degradation. What lyophilized means.
Purity and identity specifications
MT2 Labs’ stated release specification is ≥95% HPLC-UV purity with identity confirmed by LC-MS. The current lot, KB32432, reported 99.90%. How purity is measured, or how specifications fit into the quality and supply-chain process.
Analytical and testing methods
HPLC-UV for purity, LC-MS for identity and laboratory quantitation for net content, performed on every lot by Freedom Diagnostics. LAL endotoxin testing (USP <85>) and PCR microbial screening are reported for lots where they were run. Testing and quality control.
Research designation
Melanotan II is designated research use only: supplied for laboratory research by qualified personnel. Research use only policy.
Buy MT2
10 mg vials. Current lot KB32432 tested at 99.90% purity with identity confirmed by LC-MS. Current purchasing is available through Klow.bio.