Proteolytic enzymes snake toxins

The role of zinc in the enzymes listed in Table 12 is very often that of a strong Lewis acid, in which substrates are coordinated, polarized and hence activated. In other cases, zinc may play a regulatory, structural or template role. Zinc may also have a structural function in other biological molecules, for example in the unwinding and subsequent rewinding of the double-stranded polymers involved in replication and transcriptional processes. There is also evidence for a role for zinc in the stabilization of membranes and cell walls.463 The high concentrations of zinc in certain snake venoms reflect the presence in the venom of proteolytic enzymes and hemorrhagic toxins that all require zinc for activity.464... 

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