Purification and characterization of two highly different group II phospholipase A2 isozymes from a single viperid (Eristocophis macmahoni) venom.
Two phospholipase A2 isozymes have been purified from leaf-nosed viper by gel permeation chromatography followed by reverse-phase HPLC and cation-exchange FPLC. Both enzymes contain seven pairs of half-cystine, typical of group II phospholipase A2. Surprisingly large differences, affecting both N- and C-terminal regions, exist between the two isozymes purified from the same snake venom. Exchanges occur at no less than 27 of 121 positions (22%), suggesting the possible existence of two genes for phospholipase A2. The residue identity with the enzymes from other Viperidae species is also low, only 44-48%, indicating extensive variations of this protein structure at large. Functionally, the present isozymes do not possess the cationic regions ascribed to myotoxicity and anti-coagulant effects of the enzyme.
Department of Chemistry I, Karolinska Institutet, Stockholm, Sweden.
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Siddiqi
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Zaidi
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Jörnvall
D000595:Amino Acid Sequence; D000596:Amino Acids / Q000032:analysis; D000818:Animals; D007527:Isoenzymes / Q000737:chemistry* / Q000302:isolation & purification; D008969:Molecular Sequence Data; D010741:Phospholipases A / Q000737:chemistry* / Q000302:isolation & purification; D054467:Phospholipases A2; D012689:Sequence Homology, Nucleic Acid; D014757:Viper Venoms / Q000737:chemistry*
D000596:Amino Acids; D007527:Isoenzymes; D014757:Viper Venoms; D010741:Phospholipases A; D054467:Phospholipases A2