Melanotan 1 (MT1/Afamelanotide) and Melanotan 2 (MT2) are synthetic analogs of alpha-melanocyte-stimulating hormone (α-MSH) with distinct structural properties, receptor selectivity, and research applications. - Structure: Linear peptide, 13 amino acids - Sequence: Ac-Ser-Tyr-Ser-Nle-Glu-His-D-Phe-Arg-Trp-Gly-Lys-Pro-Val-NH₂ - Molecular Weight: 1,646 Da - Key modifications: Norleucine at position 4, D-phenylalanine at position 7 - Structure: Cyclic heptapeptide, 7 amino acids - Sequence: Ac-Nle-cycloAsp-His-D-Phe-Arg-Trp-Lys-NH₂ - Molecular Weight: 1,024 Da - Key modification: Lactam bridge between Asp and Lys | Receptor | Melanotan 1 | Melanotan 2 | Primary Function | |----------|-------------|-------------|------------------| | MC1R | +++++ (High) | ++++ (High) | Pigmentation | | MC2R | + (Minimal) | + (Minimal) | ACTH/cortisol | | MC3R | + (Low) | +++ (Moderate) | Energy homeostasis | | MC4R | + (Low) | +++++ (Very High) | Sexual function, appetite | | MC5R | ++ (Moderate
Melanotan 1 & 2: Melanocortin Peptide Research Guide
Comprehensive comparison of Melanotan 1 (Afamelanotide) and Melanotan 2, synthetic α-MSH analogs studied for pigmentation, photoprotection, and melanocortin receptor research.