Substrate specificity of a hemorrhagic proteinase from timber rattlesnake venom

The substrate specificity of hemorrhagic proteinase IV (HP-IV) from timber rattlesnake (Crotalus horridus horridus ) venom has been investigated. Results obtained from the hydrolysis of the various substrates by HP-IV suggest that cleavage points are determined by the size and conformation of the substrate, not just by recognition of the amino acids comprising the cleaved peptide bond.