title: Purification and inhibitory profile of phospholipase A2 inhibitors from Australian elapid sera.
abstract: Although the resistance of snakes to their own venom is well known, until now no investigators have examined the serum of Australian snakes. Here we describe the identification and purification of a range of phospholipase A(2) (PLA(2)) inhibitors from the serum of Australian elapids. All PLA(2) inhibitors were composed of two protein chains, an alpha-chain and a beta-chain. The alpha-chains were approx. 22.5 kDa in size and variably glycosylated, whereas the beta-chains were approx. 19.8 kDa in size and not glycosylated. Identification of isoforms of the two subunit chains was significant because three of the six sera examined were from single snake specimens. In addition, the glycosylation patterns of the alpha-chains were thoroughly investigated in these unpooled sera. The functional and structural properties of the purified inhibitors were studied. Uniquely, a snake PLA(2) inhibitor was found to inhibit human type II PLA(2) enzyme, which has implications for the treatment of the many diseases in which PLA(2) enzymes have been implicated. Further, we demonstrate that the inhibitor forms a non-covalent association with a purified PLA(2) enzyme. Finally, the purified PLA(2) inhibitor was shown to protect in vivo against the lethal affects of a homologous PLA(2) enzyme, suggesting a role for PLA(2) inhibitors in the treatment of snake bite victims.
authors.affiliation: Toxin Research Group, Department of Cell and Molecular Biology, University of Technology, Sydney, Westbourne Street, Gore Hill, NSW 2065 Australia.
authors.forename: P G
authors.initials: PG
authors.lastname: Hains
authors.forename: K W
authors.initials: KW
authors.lastname: Broady
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D001315:Australia; D001514:Bee Venoms / Q000037:antagonists & inhibitors / Q000201:enzymology / Q000633:toxicity; D002851:Chromatography, High Pressure Liquid; D004546:Elapid Venoms / Q000037:antagonists & inhibitors* / Q000201:enzymology* / Q000378:metabolism / Q000633:toxicity; D017815:Elapidae / Q000097:blood*; D004791:Enzyme Inhibitors / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism / Q000494:pharmacology*; D006031:Glycosylation; D006801:Humans; D013058:Mass Spectrometry; D051379:Mice; D008970:Molecular Weight; D010179:Pancreas / Q000201:enzymology; D010741:Phospholipases A / Q000037:antagonists & inhibitors* / Q000302:isolation & purification / Q000378:metabolism / Q000633:toxicity; D054467:Phospholipases A2; D011485:Protein Binding; D020033:Protein Isoforms / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism / Q000494:pharmacology; D013552:Swine
chemical_list: D001514:Bee Venoms; D004546:Elapid Venoms; D004791:Enzyme Inhibitors; D020033:Protein Isoforms; C005082:notexin; D010741:Phospholipases A; D054467:Phospholipases A2