Heterodimer CA-CB: Crotoxin is a potent presynaptic neurotoxin that possesses phospholipase A2 (PLA2) activity and exerts a lethal action by blocking neuromuscular transmission (PubMed:17203389, PubMed:16003952). It consists of a non-covalent association of a basic and weakly toxic PLA2 subunit (CB), with a small acidic, non-enzymatic and non-toxic subunit (CA also named crotapotin). The complex acts by binding to a specific 48-kDa protein (R48) receptor located on presynaptic membranes, forming a transient ternary complex CA-CB-R48, followed by dissociation of the CA-CB complex and release of the CA subunit. At equilibrium, only the CB subunits remain associated with the specific crotoxin receptor. In addition to neurotoxicity, crotoxin has been found to exert nephrotoxicity, and cardiovascular toxicity. Moreover, anti-inflammatory, immunomodulatory, anti-tumor and analgesic effects of crotoxin have also been reported (By similarity). Monomer CB: The basic subunit of crotoxin is a snake venom phospholipase A2 (PLA2) that exhibits weak neurotoxicity (PubMed:17203389, PubMed:16003952) and strong anticoagulant effects by binding to factor Xa (F10) and inhibiting the prothrombinase activity (By similarity). In addition, it exerts myotoxicity (PubMed:17203389, PubMed:16003952, PubMed:17915277), nephrotoxicity, and cardiovascular toxicity as well as anti-inflammatory, immunomodulatory, anti-tumor and analgesic effects (By similarity). Also shows a strong antimicrobial activity against X.axonopodis passiforae (Gram-negative) which is completely dependent on the enzymatic activity (PubMed:16003952). PLA2 catalyzes the calcium-dependent hydrolysis of the 2- acyl groups in 3-sn-phosphoglycerides. a 1,2-diacyl-sn-glycero-3-phosphocholine + H2O = a 1-acyl-sn-glycero-3-phosphocholine + a fatty acid + H(+) Binds 1 Ca(2+) ion. Heterodimer of one acidic (CA also named crotapotin) and one basic (CB) subunits; non-covalently linked. Expressed by the venom gland. Belongs to the phospholipase A2 family. Group II subfamily. D49 sub-subfamily.