Studies on the specificity of CNF, a phospholipase A(2) inhibitor isolatedfrom the blood plasma of the South American rattlesnake (Crotalus durissusterrificus). I. Interaction with PLA(2) from Lachesis muta muta snake venom

A phospholipase A(2) inhibitor has been previously purified and cloned from the blood plasma of the South American rattlesnake, Crotalus durissus terr ificus. This inhibitor, named CNF for Crotahus neutralizing factor, interac ts with crotoxin, the main neurotoxin from C. d. terrificus venom, abolishi ng its phospholipase A(2) activity. Crotoxin is a heterodimer of an acidic subunit (CA) and a basic phospholipase A(2) (CB). CNF acts by forming a sta ble non-toxic complex with CB, replacing CA in the toxic CA-CB of crotoxin. In the present investigation, we have shown that CNF has a broader specific ity. It is able to inhibit the PLA(2) activity of the whole venom from the bushmaster snake (Lachesis muta muta), a species evolutionary related to Cr otalus. Inhibition experiments have been carried out with four PLA(2) activ e components isolated from L. m. muta venom, one basic and three acidic one s. CNF inhibition is not restricted to the basic PLA(2), but extended to th e three acidic forms as well. (C) 1999 Elsevier Science Ltd. All rights res erved.