title: Mechanism of in vivo anticoagulant and haemolytic activity by a neutral phospholipase A(2) purified from Daboia russelii russelii venom: correlation with clinical manifestations in Russell's Viper envenomed patients.
abstract: A 13.0 kDa neutral phospholipase A2 (NEUPHOLIPASE) purified from venom of Daboia russelii russelii from eastern India was identified by peptide mass fingerprinting analysis. It exerted dose-dependent PLA2, anticoagulant and indirect haemolytic activities. NEUPHOLIPASE showed preferential binding followed by hydrolysis of phosphatidylserine > phosphatidylcholine >> phosphatidylethanolamine. Circular dichroism analysis of NEUPHOLIPASE showed a high content of alpha helix (54.6%) followed by beta-turn (29.7%) in its secondary structure. Gas-chromatographic analysis of plasma from PLA2-treated mice suggested preferential hydrolysis of pro-coagulant phospholipid PS was the primary mechanism to account for in vivo anticoagulant effect of NEUPHOLIPASE. The NEUPHOLIPASE-treated mice blood showed a significant decrease (p < 0.01) in WBC as well as RBC counts with a corresponding decline in Hb content due to indirect damage to erythrocyte membranes by plasma phospholipids hydrolysis products rather than the direct haemolytic activity of PLA2 under study. NEUPHOLIPASE was non-lethal to BALB/c mice, however; it was detrimental to liver of treated-mice. Pathological symptoms observed in NEUPHOLIPASE-treated mice were correlated with the actual clinical manifestations in Russell's Viper envenomed patients from eastern India indicating some contribution of NEUPHOLIPASE in Russell's Viper venom induced toxicity and pathogenesis.
authors.affiliation: Microbial Biotechnology and Protein Research Laboratory, Department of Molecular Biology and Biotechnology, Tezpur University, Tezpur, Assam 784028, India.
authors.forename: Debashree
authors.initials: D
authors.lastname: Saikia
authors.forename: Sourav
authors.initials: S
authors.lastname: Majumdar
authors.forename: Ashis K
authors.initials: AK
authors.lastname: Mukherjee
mesh_terms: D000818:Animals; D000925:Anticoagulants / Q000302:isolation & purification / Q000633:toxicity*; D002849:Chromatography, Gas; D002851:Chromatography, High Pressure Liquid; D006041:Goats; D053878:Hemolytic Agents / Q000302:isolation & purification / Q000633:toxicity*; D006801:Humans; D051379:Mice; D008807:Mice, Inbred BALB C; D010449:Peptide Mapping; D054467:Phospholipases A2 / Q000302:isolation & purification / Q000633:toxicity*; D017840:Daboia; D012909:Snake Bites / Q000473:pathology*; D013379:Substrate Specificity; D014757:Viper Venoms / Q000201:enzymology / Q000633:toxicity*
chemical_list: D000925:Anticoagulants; D053878:Hemolytic Agents; D014757:Viper Venoms; D054467:Phospholipases A2
keywords: Anticoagulant activity; Haemolysis; Neutral PLA(2); Phospholipids hydrolysis; Russell's Viper venom