1. Source: from Chinese Cobra Venom 2. Description: 3. Mol wt: 4. Identification of biological activity: when assayed in vivo rat heart, it shows that, cytotoxin impermanently enhances the contraction of the cardiac muscle of the vivo heart, then weakens it quickly, after which beating rate slowers with heart contracture, and heart beating finally stops. 5. Usage fields: Cytotoxin effects on heart, mainline of this product can cause rats circulation to crock up, and in heart in vivo assay, it causes heart contracture, and even ends heart beating. It can also cause skeleton muscle and intestines smooth muscle contraction.