SNAP-8

SNAP-8, also known as acetyl octapeptide-3, is a synthetic octapeptide acetylated at the N-terminus and amidated at the C-terminus, with the sequence Ac-Glu-Glu-Met-Gln-Arg-Arg-Ala-Asp-NH2 (C42H72N16O15S, about 1073.2 g/mol). Its first six residues reproduce the acetyl hexapeptide Ac-EEMQRR-NH2 (acetyl hexapeptide-8), which was identified through a rational design program seeking peptides that interfere with the vesicle-fusion machinery; SNAP-8 extends that sequence by Ala and Asp. The octapeptide carries three acidic side chains (two Glu, one Asp) and two basic Arg side chains.

SNAP-8 in the research literature

Mechanistic data come mainly from the parent hexapeptide. In biochemical and cell-based assays, acetyl hexapeptide-8 interfered with the formation and/or stability of the SNARE complex, the vesicular fusion complex required for calcium-dependent exocytosis, and this interference was reported to underlie its inhibition of neurotransmitter release in vitro. A 2025 review of the hexapeptide described its mechanism as modulation of neuromuscular signaling while noting that key aspects of that mechanism remain incompletely understood.

Peer-reviewed studies indexed in PubMed that characterize the octapeptide itself are sparse, so its SNARE-related activity is generally inferred from the shared N-terminal sequence rather than from dedicated primary work.