Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
8397522 | Toxicon | 2013 | 9 Pages |
Abstract
Fractionation by reversed-phase HPLC of venom from four species of saw-scaled viper: Echis ocellatus, Echis pyramidum leakeyi, Echis carinatus sochureki, and Echis coloratus led to identification in each sample of an abundant protein with cytotoxic activity against human non-small cell lung adenocarcinoma A549 cells. The active component in each case was identified by MALDI-TOF mass fingerprinting of tryptic digests as [Ser49]phospholipase A2 ([Ser49]PLA2). An isoform of [Ser49]PLA2 containing the single Ala18 â Val substitution and a partially characterized [Asp49]PLA2 were also present in the E. coloratus venom. LC50 values against A549 cells for the purified [Ser49]PLA2 proteins from the four species are in the range 2.9-8.5 μM. This range is not significantly different from the range of LC50 values against human umbilical vein endothelial HUVEC cells (2.5-12.2 μM) indicating that the [Ser49]PLA2 proteins show no differential anti-tumor activity. The LC50 value for [Ser49]PLA2 from E. ocellatus against human erythrocytes is >100 μM and the MIC values against Escherichia coli and Staphylococcus aureus are >100 μM. It is suggested that the [Ser49]PLA2 proteins play a major role in producing local tissue necrosis and hemorrhage at the site of envenomation.
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Authors
J. Michael Conlon, Samir Attoub, Hama Arafat, Milena Mechkarska, Nicholas R. Casewell, Robert A. Harrison, Juan J. Calvete,