Function
While Melanotan I is approved in some regions for prevention of phototoxicity in erythropoietic protoporphyria and is studied as a skin-darkening, photoprotective peptide3444, MOTS-c improves insulin sensitivity, enhances glycolysis, reduces oxidative stress, and shows protective effects in models of metabolic syndrome, aging, and ischemia-reperfusion injury8135146.
Mechanism
While Melanotan I works as a linear 13-amino-acid analog of α-MSH (afamelanotide) that selectively activates MC1R on melanocytes, increasing eumelanin synthesis and providing photoprotection3444, MOTS-c is a 16-amino-acid mitochondrial-derived peptide that translocates to the nucleus under metabolic stress and regulates glucose and lipid metabolism largely via activation of AMPK and modulation of mTOR and folate-cycle–linked pathways854140146.
Length and Sequence
Melanotan I is 13 amino acids long, whereas MOTS-c is longer as it has a length of 16 amino acids. Melanotan I is made up of a sequence of Serine, Tyrosine, Serine, Nle, Glutamic acid, Histidine, Phenylalanine, Arginine, Tryptophan, Glycine, Lysine, Proline, Valine. MOTS-c is made up of a sequence of Methionine, Arginine, Tryptophan, Glutamine, Glutamic acid, Methionine, Glycine, Tyrosine, Isoleucine, Phenylalanine, Tyrosine, Proline, Arginine, Lysine, Leucine, Arginine.