Isolation and properties of lysophospholipases from the venom of an Australian elapid snake, Pseudechis australis. |
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| Authors: | C Takasaki and N Tamiya |
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| Abstract: | Two lysophospholipases were isolated from the venom of an Australian elapid snake (subfamily Acanthophiinae), Pseudechis australis, by sequential chromatography on CM-52 cellulose, Sephadex G-75 and DE-52 cellulose columns. They were very similar to each other. One of them, lysophospholipase I, was obtained as a homodimer, the monomer of which consisted of 123 amino acid residues with seven disulphide bridges. The amino acid composition and the N-terminal amino acid sequence of the enzyme were similar to those of phospholipase A2, Ca2+ was required for its activity and the maximum activity was attained at 2 mM-CaCl2 in the presence of 1 mM-EDTA. The optimum pH was 7.5. Lysophospholipase I hydrolysed lysophosphatidylcholine more rapidly than lysophosphatidylethanolamine. It did not hydrolyse, however, phosphatidylcholine, 1-palmitoylglycerol, tripalmitoylglycerol or p-nitrophenyl acetate. Modification of the enzyme with p-bromophenacyl bromide or 2-nitrophenylsulphenyl chloride suppressed the activity. A strong direct haemolytic activity was exhibited when the lysophospholipase was present together with phospholipase A2. |
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