Acts as a beta-blocker by binding to beta-1 and beta-2 adrenergic receptors (ADRB1 and ADRB2). It dose-dependently decreases the heart rate (bradycardia), whereas conventional cardiotoxins increases it. At 100 mg/kg, intraperitoneal injection into mice provokes labored breathing, impaired locomotion, lack of response to external stimuli, and death (after 30 min). Expressed by the venom gland. Does not affect blood coagulation and does not show significant hemolytic activity. Is classified as a P-type cytotoxin, since a proline residue stands at position 52 (Pro-31 in standard classification). Belongs to the snake three-finger toxin family. Short-chain subfamily. Aminergic toxin sub-subfamily.