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Three lactose-inhibited lectins from the venoms of the snakes Agkistrodon
contortrix contortrix (southern copperhead), Ancistrodon piscivorous leukostoma
(western cottonmouth moccasin) and Crotalus atrox (western diamondback
rattlesnake) have been isolated and newly characterized. The three lectins are
similar to thrombolectin, a lectin isolated from the venom of Bothrops atrox
(fer-de-lance) (Gartner, Stocker & Williams, 1980), with regard to sugar
specificity, Mr, Ca2+ requirements and sensitivity to reducing agents. Each
lectin is a dimer (Mr 28 000) consisting of monomers (Mr 14 000)
indistinguishable on sodium dodecyl sulphate/polyacrylamide-gel electrophoresis.
Haemagglutination activity is dependent on the presence of Ca2+ and is inhibited
by reducing agents. The lectins are not identical and can be distinguished on
the basis of relative affinities for inhibiting sugars, isoelectric points and
immunoprecipitation assays using anti-(cottonmouth lectin) serum.
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