Selectively binds with high-affinity to the a2B-adrenoceptor subtype (ADRA2B) (PubMed:20466015). The toxin reversibly binds to ADRA2B, and its mode of inhibition is non-competitive (PubMed:20466015). The toxin has also been described to bind with high affinity to all muscarinic receptor subtypes (Ki=23 nM (on CHRM1), Ki=44 nM (on CHRM2), Ki=3 nM (on CHRM3), Ki=5 nM (on CHRM4), and Ki=8 nM (on CHRM5)) but no other data support these affinity values (PubMed:8536706). Expressed by the venom gland. Does not affect most adrenoceptors (ADRA1A, ADRA1B, ADRA2A AND ADRA2C) and muscarinic receptors (PubMed:20466015, PubMed:21557730). Does not affect beta-1 (ADRB1) and beta-2 (ADRB2) adrenoceptors (PubMed:21557730). Belongs to the snake three-finger toxin family. Short-chain subfamily. Aminergic toxin sub-subfamily.