Snake venom phospholipase A2 homolog that lacks enzymatic activity. Has myotoxic activities (PubMed:9920492). A model of myotoxic mechanism has been proposed: an apo Lys49-PLA2 is activated by the entrance of a hydrophobic molecule (e.g. fatty acid) at the hydrophobic channel of the protein leading to a reorientation of a monomer (By similarity). This reorientation causes a transition between 'inactive' to 'active' states, causing alignment of C-terminal and membrane-docking sites (MDoS) side-by-side and putting the membrane-disruption sites (MDiS) in the same plane, exposed to solvent and in a symmetric position for both monomers (By similarity). The MDoS region stabilizes the toxin on membrane by the interaction of charged residues with phospholipid head groups (By similarity). Subsequently, the MDiS region destabilizes the membrane with penetration of hydrophobic residues (By similarity). This insertion causes a disorganization of the membrane, allowing an uncontrolled influx of ions (i.e. calcium and sodium), and eventually triggering irreversible intracellular alterations and cell death (By similarity). Heparin and wedelolactone inhibit the myotoxic activity (PubMed:9920492). The PLA2 inhibitor, para-bromophenacyl bromide (BPB), inhibits the myotoxic activity (PubMed:9920492). Binds to heparin (PubMed:9920492). Expressed by the venom gland. Belongs to the phospholipase A2 family. Group II subfamily. K49 sub-subfamily. Does not bind calcium as one of the calcium-binding sites is lost (Asp->Lys in position 64, which corresponds to 'Lys-49' in the current nomenclature).