Identification of Cardiotoxin with Cobramine B, DLF, Toxin and Cobra Venom Cytotoxin
NATIONAL TAIWAN UNIV TAIPEI PHARMACOLOGICAL INST
Pagination or Media Count:
Cardiotoxin, Cobramine B, the direct hemolytic factor DLF and cobra venom cytotoxin are all the most basic polypeptides isolated from cobra venom. Cardiotoxin affects various kinds of cells, causing irreversible depolarization of cell membrane. It causes contracture of skeletal muscle, systolic arrest of the heart, contraction of smooth muscle, block of axonal conduction, local irritation, etc. Cardiotoxin has a weak direct hemolytic activity on washed erythrocytes of guinea pig, dog and cat, and shows cytopathic effects on stable tumor cell cultures HeLa, KB. Both the contracture-inducing and direct hemolytic activities of cardiotoxin can be potentiated by phospholipase A, and prevented by polyanions gangliosides, RNA and heparin, just as the inhibition of iodide accumulation in thyroid slices by cobramine B. Moreover, the amino acid composition and molecular weight of cardiotoxin are almost identical with those of cobramine B. From these results, it is concluded that cobramine B, DLF, and possibly cobra venom cytotoxin are all identical with cardiotoxin.