Synaptobrevins (synaptobrevin isotypes 1-2) are small integral membrane proteins of secretory vesicles with molecular weight of 18 kilodalton (kDa) that are part of the vesicle-associated membrane protein (VAMP) family.

SNARE proteins are the key components of the molecular machinery that drives fusion of membranes in exocytosis.

Their function however is subject to fine-tuning by various regulatory proteins collectively referred to as SNARE masters.

In the Q/R nomenclature for organizing SNARE proteins, VAMP/synaptobrevin family members are classified as R-SNAREs, so named for the presence of an arginine at a specific location within the primary sequence of the protein (as opposed to the SNAREs of the target membrane, which contain a glutamine and are so named Q-SNAREs).

[6] Synaptobrevin is degraded by tetanospasmin, a protein derived from the bacterium Clostridium tetani, which causes tetanus.