Function
While PEG-MGF is used experimentally to enhance muscle repair and hypertrophy after mechanical overload or injury by stimulating satellite-cell activation and protein synthesis6373138, Snap-8 is a cosmetic peptide studied for reducing wrinkle depth by inhibiting synaptic vesicle fusion and subsequent muscle contraction in facial expression muscles5060.
Mechanism
While PEG-MGF works as a poly(ethylene glycol)-conjugated form of Mechano Growth Factor (IGF-1Ec splice variant) comprising the 24-aa C-terminal E-peptide of IGF-1, designed to extend half-life while activating IGF-1 receptor–mediated anabolic signaling in muscle satellite cells637322138, Snap-8 is acetyl octapeptide-3 (Ac-Glu-Glu-Met-Gln-Arg-Arg-Ala-Asp-NH2), an extended analog of Argireline derived from the N-terminal region of SNAP-25 that competes with native SNAP-25 for binding to syntaxin-1, forming a non-functional SNARE complex and reducing neurotransmitter release5060.
Length and Sequence
PEG-MGF is 24 amino acids long, whereas Snap-8 is shorter as it has a length of 8 amino acids. PEG-MGF is made up of a sequence of Tyrosine, Glutamine, Proline, Proline, Serine, Threonine, Asparagine, Lysine, Asparagine, Threonine, Lysine, Serine, Glutamine, Arginine, Arginine, Lysine, Glycine, Serine, Threonine, Phenylalanine, Glutamic acid, Glutamic acid, Arginine, Lysine. Snap-8 is made up of a sequence of Glutamic acid, Glutamic acid, Methionine, Glutamine, Arginine, Arginine, Alanine, Aspartic acid.