[Proteolytic, procoagulant activity and electrophoretic characterization of the proteins of 2 toxic extracts of Loxosceles laeta venom].

Some biochemical properties and proteic components of the brown spider (Loxos celes laeta) venom were studied. The electrophoretic profiles of glandular venom and venom obtained through electrical stimulation were compared using two electrophoretic systems. The first, using a polyacrylamide gel with SDS in tubes, and the second, using an acrylamide gradient on slides. The glandular venom presented 20 and 35 bands respectively, while the venom obtained through electrical stimulation presented 19 and 24 bands. The molecular weight of the proteins detected ranged from 13.5 Kd to 220 Kd. A thermolabil proteolitic activity of casein was detected, and was optimum at pH 9. The effects of the divalent ions, calcium and magnesium, as well as that of chelating agents upon the proteolytic activity of the venom were analyzed. The venom had a procoagulant effect upon citrated human plasma, and was not able to activate the Factor X of the coagulation system in vitro.