Crotoxin. I. Immunology and interaction of the subunits

Abstract

p6ospholipase A and crotapotin were purified by gel filtration and ion-exchange chromatography from Crotalus durissus terrificus venom. The minimal molecular weights obtained by amino acid analysis were 13,400 daltons for phospholipase A and 8,300 daltons for crotapotin. Phospholipase A and crotapotin form a 1:1 molar complex that was stable during gel filtration. The LD50 of phospholipase A was increased about 10-fold when in a 1:1 complex with crotapotin. Crotapotin, phospholipase A and crotoxin (crotapotin + phospholipase A) gave precipitin reactions when tested with specific rabbit antisera. Immunological studies of these proteins using crotalus antiserum confirmed 1:1 molar ratio of the complex. Crotoxin antiserum also reacts with either crotapotin or phospholipase A separately. Similar antigenic determinants were observed in the subunits and it seems that some antigenic determinants are masked in the phospholipase A-crotapotin complex.