title: Purification and preliminary characterisation of praelongin phospholipases, antiplatelet agents from the snake venom of Acanthophis praelongus.
abstract: Three praelongin phospholipases were chromatographically purified from the snake venom of Acanthophis praelongus. The purity and homogeneity of the praelongins were assessed by RP-HPLC, HPCE and mass spectrometry. The purified enzymes, praelongins 2bIII, 2cII and 2cIV were found to have phospholipase A2 activities with specific activities of 31.4 +/- 0.4, 326.1 +/- 10.2 and 362.5 +/- 12.0 U/mg, respectively. Mass spectrometry studies showed the molecular mass of praelongin 2bIII to be 12,782.9 +/- 2.6 and praelongins 2cII and 2cIV to have very similar molecular mass values, 12,971.4 +/- 4.5 and 12,971.9 +/- 3.6, respectively. However, platelet aggregation studies showed the praelongins to display different IC50 values, 180 microM for praelongin 2cII and 55 microM for praelongin 2cIV; praelongin 2bIII was found to be a more potent antiplatelet agent, having an IC50 of 0.65 microM. Praelongins 2bIII, 2cIV and 2cII were found to have pI values of 10.3 +/- 0.3, 9.6 +/- 0.6 and 9.4 +/- 0.6 as determined by HPCE. The antiplatelet potencies do not correspond to their in vitro phospholipase catalytic potencies, but appear to be related to the enzyme isoelectric points.
authors.affiliation: Bioscience Centre, Faculty of Science, National University of Singapore, Singapore. bscsimkl@nus.sg
authors.forename: K L
authors.initials: KL
authors.lastname: Sim
mesh_terms: D000818:Animals; D002851:Chromatography, High Pressure Liquid; D004546:Elapid Venoms / Q000737:chemistry / Q000201:enzymology* / Q000494:pharmacology; D019075:Electrophoresis, Capillary; D006801:Humans; D066298:In Vitro Techniques; D007526:Isoelectric Point; D007527:Isoenzymes / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D013058:Mass Spectrometry; D008970:Molecular Weight; D010741:Phospholipases A / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D054467:Phospholipases A2; D010974:Platelet Aggregation / Q000187:drug effects; D010975:Platelet Aggregation Inhibitors / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D011517:Prothrombin Time
chemical_list: D004546:Elapid Venoms; D007527:Isoenzymes; D010975:Platelet Aggregation Inhibitors; D010741:Phospholipases A; D054467:Phospholipases A2