Heterodimer: slightly affects neuromuscular transmission acting presynaptically. It has a low catalytic activity, a low anticoagulant activity and weakly inhibits ADP-induced platelet aggregation. Monomer: has no activity (neurotoxic, catalytic, anticoagulant and a ADP-induced platelet aggregation), but inhibits phospholipase A2. Heterodimer of an acidic and a basic chain; non-covalently linked. The basic chain is toxic and has phospholipase A2 activity (chain HDP-1P (AC Q1RP79) or HDP-2P (AC Q1RP78)) and the acidic chain is non-toxic and functions as its inhibitor (chain HPD-1I). Expressed by the venom gland. Belongs to the phospholipase A2 family. Group II subfamily. D49 sub-subfamily. In contrast to other phospholipases, it lacks the typical His active site (His->Gln in position 63).