Purification, characterization, and amino acid sequence determination of acanthins, potent inhibitors of platelet aggregation from Acanthophis antarcticus (common death adder) venom

• Published in: Archives of biochemistry and biophysics Vol. 354; no. 2; p. 232
• Main Authors: Chow, G, Subburaju, S, Kini, R M
• Format: Journal Article
• Language: English
• Published: United States 15.06.1998
• Subjects: Amino Acid Sequence; Amino Acids - analysis; Animals; Elapid Venoms - chemistry; Elapid Venoms - isolation & purification; Elapid Venoms - pharmacology; Elapidae; Humans; In Vitro Techniques; Molecular Sequence Data; Platelet Aggregation Inhibitors - chemistry; Platelet Aggregation Inhibitors - isolation & purification; Platelet Aggregation Inhibitors - pharmacology
• ISSN: 0003-9861
• DOI: 10.1006/abbi.1998.0685

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.