title: Purification, characterization, and amino acid sequence determination of acanthins, potent inhibitors of platelet aggregation from Acanthophis antarcticus (common death adder) venom.
abstract: Venom of Acanthophis antarcticus, a common death adder, exhibits potent antiplatelet effects. By a combination of gel-filtration, cation-exchange, and reversed-phase chromatographic methods, two inhibitors of platelet aggregation, named acanthin I and II, were purified to homogeneity as assessed by capillary electrophoresis and electrospray mass spectrometry. These isoforms exhibit the most potent antiplatelet activity known thus far, with IC50 values of 7 nM for acanthin I and 4 nM for acanthin II in human whole blood when collagen was used as an agonist, whereas with ADP the IC50 values were 10 and 12 nM, respectively. Acanthin I and II are basic proteins with pIs of 10.2 +/- 0.1 and 10.4 +/- 0.1 and molecular weights of 12,844.58 +/- 0.61 and 12,895.63 +/- 0.48, respectively, as determined by electrospray mass spectrometry. They exhibit phospholipase enzyme activity, and acanthin I and II hydrolyzed 51. 57 +/- 1.30 and 46.85 +/- 2.90 micromol of phosphatidylcholine/min/mg, respectively. The complete amino acid sequences of acanthin I and II showed that they have a high homology with each other and with other elapids' phospholipase A2 neurotoxin, especially pseudexin A.
authors.affiliation: Faculty of Science, National University of Singapore, 119260, Singapore.
authors.forename: G
authors.initials: G
authors.lastname: Chow
authors.forename: S
authors.initials: S
authors.lastname: Subburaju
authors.forename: R M
authors.initials: RM
authors.lastname: Kini
mesh_terms: D000595:Amino Acid Sequence; D000596:Amino Acids / Q000032:analysis; D000818:Animals; D004546:Elapid Venoms / Q000737:chemistry* / Q000302:isolation & purification* / Q000494:pharmacology; D017815:Elapidae; D006801:Humans; D066298:In Vitro Techniques; D008969:Molecular Sequence Data; D010975:Platelet Aggregation Inhibitors / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology
chemical_list: D000596:Amino Acids; D004546:Elapid Venoms; D010975:Platelet Aggregation Inhibitors; C112921:acanthin