title: Purification and properties of three new phospholipase A2 isoenzymes from Micropechis ikaheka venom.
abstract: Three new phospholipase A2 (PLA2) isoenzymes were purified from the Micropechis ikaheka venom by successive chromatographies. The homogeneity of them was accessed by capillary zone electrophoresis and mass spectrometry. Their N-terminal sequences showed high identity (94, 88 and 90, respectively) with MiPLA-1, a group IB PLA2 also from this venom. In addition, strong immuno-cross-reaction with anti-MiPLA-1 serum was observed. These results suggested that three newly purified PLA2 belonged to group IB. Beside enzymatic activity, they induced various pharmacological effects, including myotoxic, anticoagulant effects and insulin secretion stimulating effects. Our results indicated that enzymatic activity is essential for their myotoxic and anticoagulant effects. On the other hand, no direct correlation between their insulin secretion stimulating effect and enzymatic activity was observed, suggesting that they may stimulate insulin secretion through a non-enzymatic mechanism.
authors.affiliation: Venom and Toxin Research Programme, Department of Anatomy, National University of Singapore, Singapore.
authors.forename: R
authors.initials: R
authors.lastname: Gao
authors.forename: R M
authors.initials: RM
authors.lastname: Kini
authors.forename: G
authors.initials: G
authors.lastname: Li
authors.forename: R
authors.initials: R
authors.lastname: Luo
authors.forename: Z E
authors.initials: ZE
authors.lastname: Selvanayagam
authors.forename: P
authors.initials: P
authors.lastname: Gopalakrishnakone
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001777:Blood Coagulation / Q000187:drug effects; D002478:Cells, Cultured / Q000187:drug effects; D002850:Chromatography, Gel; D004546:Elapid Venoms / Q000201:enzymology* / Q000276:immunology / Q000302:isolation & purification* / Q000378:metabolism / Q000494:pharmacology; D017815:Elapidae / Q000378:metabolism*; D019075:Electrophoresis, Capillary; D054500:Group IB Phospholipases A2; D054501:Group II Phospholipases A2; D007106:Immune Sera; D007328:Insulin / Q000378:metabolism; D000078790:Insulin Secretion; D007515:Islets of Langerhans / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D007527:Isoenzymes / Q000302:isolation & purification* / Q000378:metabolism / Q000494:pharmacology; D051379:Mice; D008969:Molecular Sequence Data; D008970:Molecular Weight; D018482:Muscle, Skeletal / Q000187:drug effects / Q000473:pathology; D010741:Phospholipases A / Q000276:immunology / Q000302:isolation & purification* / Q000378:metabolism / Q000494:pharmacology; D054467:Phospholipases A2; D011517:Prothrombin Time; D011817:Rabbits; D030162:Reptilian Proteins; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D021241:Spectrometry, Mass, Electrospray Ionization; D013918:Thrombin Time
chemical_list: D004546:Elapid Venoms; D007106:Immune Sera; D007328:Insulin; D007527:Isoenzymes; D030162:Reptilian Proteins; C427220:MiPLA-4 protein, Micropechis ikaheka; D010741:Phospholipases A; D054500:Group IB Phospholipases A2; D054501:Group II Phospholipases A2; D054467:Phospholipases A2