Hey I was wondering if anybody ever compared the Amino Acid Sequence between melanotan-1, melanotan II and afamelanotide (CUV 1647) (which is the product tested by Clinuvel) and could give the Sequences to me.
I was trying to figure out which Peptide has been tested best and is actually tested by Clinuvel. Does Clinuvel give their Sequence to the public?
 
This is all I could find about about it on Clinuvel:
afamelanotide (CUV 1647) is a chemical analogue of -MSH. afamelanotide (CUV 1647) is a linear peptide with 13 amino acids. Two amino acids present in -MSH have been changed to produce afamelanotide (CUV 1647).
 
And this is what I found about the Sequence from Sinopep:
Sequence: Ac-Nle-Asp-His-D-Phe-Arg-Trp-Lys-NH2(Lactam Bridge:2-7)
Formula C50 H69 N15 O9
On the page of aquastealth.
 
melanotan IItan gives following sequence: Ac-Nle-cyclo(Asp-His-D-Phe-Arg-Trp-Lys)-NH2
 
melanocoprs sequence:
Ac-Nle-Asp-His-(D-Phe)-Arg-Trp-Lys-NH2
 
As far as I see, the all the inofficial Peptide have just 9 Amino Acid and a NH2 group instead of the 13 mentioned by Clinuvel and aditionaly all three sequences I found have minor differences regarding to the parentheses and that melanotan IItan says that theyer's seems to be cyclic, which in turn would not be linear like afamelanotide (CUV 1647). Now my question: ARE THOSE ALL THE SAME PEPTIDES?

Hausse,
You pose an interesting question.
Yes that is the only information I can gather from Clinuvel- They have changed two of the amino acids. Perhaps by doing this they have found a way to make the molecule more stable, since it is implanted at body heat and yet does not degrade for (I think) up to 3 months per implant.
 
I would speculate that there are many analogues of a-MSH, each may stimulate different melanocortin receptors.
 
There is a study going on with a four amino acid analogue of a-MSH that may be able to penetrate the skin as a topical tanning cream.
 
Keep up the searchs and we may be able to find answers.

So but if I see this right, the only big and reliable study is made with an other peptide?

Hi All,
 
FYI, immediately below are JPGs of the melanotan-1 and melanotan II molecules.  One can immediately see how different they really are.

melanotan II Molecule - It is significantly lighter and smaller than melanotan-1.  It's ring structure gives it additional stability, and allows it to cross the blood-brain barrier and bind to MC3 and MC4 receptors, whereas melanotan-1 cannot.  This gives rise the the "sides" of erections and digestive effects, among others.
 
Note 1 - these are not really side effects of melanotan II, but are on the exact same level as it's binding to MC1, resulting in tanning.
 
Note 2 - the molecular structure of melanotan II results in it being 5-10 times more potent for tanning per milligram than melanotan-1, based on dosing and results seen on this forum (my observation).

Good pics, MSHie. Where did you find those? Also, you don't happen to know the correct amino acid sequence for melanotan II, do you?

Hey Pseudo, go to http://pubchem.ncbi.nlm.nih.gov and search for Melanotan.  Two melanotan II compounds show up with very similar (but not exactly the same) IUPAC names.  They both have exactly the same molecular weight, though.  I suspect they are isomers.
 
The posted JPG is of (3S,6S,9R,12S,15S,23S) -15- [[(2S)-2-acetamidohexanoyl]amino] -9- (cyclohexylmethyl) -6- [3-(diaminomethylideneamino)propyl] -12- (3H-imidazol-4-ylmethyl) -3- (1H-indol-3-ylmethyl) -2,5,8,11,14,17- hexaoxo -1,4,7,10,13,18- hexazacyclotricosane -23- carboxamide.