title: Rapid activation of the non-toxic basic isoform of phospholipase A2 from Naja mossambica mossambica (spitting cobra) by long-chain fatty acylation.
abstract: Purified phospholipase A2 from Naja naja (common Indian cobra) venom, a basic non-toxic isoform and a toxic isoform from Naja mossambica mossambica venom were treated with an equimolar amount of oleoyl imidazolide, a known activator of bee venom phospholipase A2. The ability of the first two enzymes to induce erythrocyte lysis was strongly activated while hydrolysis of dioctanoyl phosphatidyl choline was only weakly activated. The toxic enzyme showed little change in either assay. The susceptible enzyme from Naja mossambica mossambica venom reacted very much more rapidly with oleoyl imidazolide than did the bee venom enzyme and oleic acid was shown to be a relatively weak antagonist. Activation had very little effect on the metal ion dependence of these enzymes. Although activation was a progressive response having the characteristics of a chemical reaction which could not be mimicked by free fatty acids, the adduct did not appear to be stable under acidic conditions. This evidence suggested that primary amino groups were not the target for acylation.
authors.affiliation: Department of Cell Biology, University of Glasgow, Scotland, U.K.
authors.forename: S
authors.initials: S
authors.lastname: Chettibi
authors.forename: F
authors.initials: F
authors.lastname: Lyall
authors.forename: A J
authors.initials: AJ
authors.lastname: Lawrence
mesh_terms: D000215:Acylation; D000595:Amino Acid Sequence; D000818:Animals; D001514:Bee Venoms / Q000378:metabolism; D004546:Elapid Venoms / Q000737:chemistry*; D004591:Electrophoresis, Polyacrylamide Gel; D004789:Enzyme Activation; D004912:Erythrocytes / Q000378:metabolism; D005227:Fatty Acids / Q000378:metabolism*; D006868:Hydrolysis; D007527:Isoenzymes / Q000302:isolation & purification*; D007700:Kinetics; D008969:Molecular Sequence Data; D010741:Phospholipases A / Q000302:isolation & purification*; D054467:Phospholipases A2; D011817:Rabbits
chemical_list: D001514:Bee Venoms; D004546:Elapid Venoms; D005227:Fatty Acids; D007527:Isoenzymes; D010741:Phospholipases A; D054467:Phospholipases A2