LOW-MOLECULAR-WEIGHT COMPONENTS FROM BLACK-WIDOW SPIDER VENOM

Highly purified alpha-latrotoxin from the black widow spider venom (al pha-LTX) consists of two polypeptides with mel. wts of 130,000 and 800 0 (LMWP). We have isolated two low mol. wt proteins LMWP and LMWP2 fro m the low mol. wt fraction of this venom. The chemical properties of t hese proteins and partial amino acid sequence of novel protein LMWP2 w ere studied. By means of i.v. or intracerebroventricular injections in to mice it was shown that low mol. wt components of the venom at conce ntrations of 2.3 mg/kg and 0.8 mg/kg, respectively, did not possess an y direct toxic effect on vertebrates. Injections of each protein into the third thoracic segment of cockroaches Periplaneta americana (doses up to 80 mu g/g) did not cause lethality or paralysis of insects.