Characterisation of a purified phospholipase A₂ from the venom of the Papuan black snake (Pseudechis papuanus)

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• 作者：Laing ; Gavin D. ; Kamiguti ; Aura S. ; Wilkinson ; Mark C. ; Lowe ; Gordon M. ; Theakston ; R. David G.
• 关键词：Venom PLA₂ ; Platelet inhibitor ; Anticoagulant
• 刊名：Biochimica et Biophysica Acta (BBA)/Protein Structure and Molecular Enzymology
• 出版年：1995
• 出版时间：July 19, 1995
• 年：1995
• 卷：1250
• 期：2
• 页码：137-143
• 全文大小：769 K

文摘

A neutral phospholipase A₂ (PLA₂) was separated from Pseudechis papuanus venom by a two-stage FPLC procedure of cation exchange and phenyl-Superose chromatography. It had a molecular mass of 15 kDa and a lower LD₅₀ value than a co-separated haemorrhagic fraction, indicating a higher lethal potency. In vitro tests confirmed the powerful inhibition of platelet aggregation by the PLA₂ and strong anticoagulant activity initially observed with whole venom. Ultrastructural studies showed that platelets lost their discoid shape and developed membranous projections with a general decrease in electron-density of the cytosol and disruption of the microfilaments following incubation with the enzyme. Amino acid sequence analysis of the N-terminus and some internal peptides demonstrated a high degree of homology with PLA₂s from other Pseudechis venoms. Our results indicate that this fraction is the main agent responsible for the haemostatic disorders in envenomed patients.