Comparative study of three phospholipase A 2s from the venom of Vipera aspis

Abstract

1. 1. Three phospholipase A 2s, PLA 2-I, PLA 2-II and PLA 2-III, were isolated from Vipera aspis venom by gel filtration and ion exchange chromatography. 2. 2. Purified PLA 2-I, -II and -III have mol. wts of 30,200, 16,000 and 13,500, and isoelectric points of 9.45, 7.65 and <4.1, respectively. 3. 3. PLA 2-I consists of an acidic subunit (mol. wt 13,700, pI: <3.5) and a basic subunit (mol. wt 16,500, pI: 10.6), which can be separated under highly acidic conditions. 4. 4. PLA 2-I possessed lethal activity and LD 50 for this preparation was estimated to be 0.288 (0.209–0.397) μg/g, while lethality was not observed when PLA 2-II, -III or each subunit of PLA 2-I were administered. 5. 5. Capillary permeability-increasing activity was found in the samples which possessed basic isoelectric points. Additionally, PLA 2-I and its basic subunit drastically prolonged activated partial thromboplastin time of platelet rich plasma. 6. 6. Intramuscular injections of PLA 2-I, -II and -III increased serum creatine phosphokinase activity in mice, indicating that damage in muscle was caused by these enzymes. 7. 7. NH 2-terminal sequences of the three PLA 2-s were compared with other phospholipase A 2s from snake venoms. Furthermore, antigenicities were tested using antiserum prepared against each sample.