Isolation of minax toxins from the venom of the scorpion Buthus minax and their metabolic effects.

Two neurotoxins, minax toxins 1 and 2, were isolated from venom of the scorpion Buthus minax from the Sudan. Molecular weights of 7000 and 6800 and 66 and 62 amino acids were found for minax toxins 1 and 2, respectively. Both toxins contain four disulfide bonds, 1 mol each of phenylalanine, histidine, and tryptophan, no free sulfhydryl groups, and no methionine. Both minax toxins 1 and 2 are basic polypeptides with isoelectric points of 8.2 and 9.0, respectively. There is a significant increase in the calcium content of rat hearts envenomated with minax toxins 1 and 2 or crude venom. This confirms earlier electron microscopic findings of calcium deposits in the heart following scorpion envenomation. There is a concomitant decrease in the calcium and phosphorus content of rat serum following envenomation. It seems that neither scorpion toxins nor scorpion venoms affect the mineral metabolism of the bone. The present investigation indicates that scorpion toxins have not only a neurotoxic action but also broader biological effects such as mineral metabolism.