Resistance of a hemorrhagic proteinase from timber rattlesnake venom to proteolytic degradation

Abstract

The proteolytic activity of hemorrhagic proteinase IV isolated from timber rattlesnake ( Crotalus horridus horridus) venom was resistant to inactivation by trypsin, pronase and the proteolytic II, fraction isolated from timber rattlesnake venom. SDS-polyacrylamide gel electrophoresis of the hemorrhagin incubated alone and with the three proteinases revealed that the addition of trypsin or the II, fraction caused little apparent degradation of the hemorrhagin, whether or not the samples were reduced prior to electrophoresis. SDS electrophoresis of the hemorrhagin after incubation with pronase revealed a single band of 28,000 apparent molecular weight (as compared to 52,000 for the original hemorrhagin) if the samples were not reduced prior to electrophoresis, and a single band of 17,000 if reduced. If the hemorrhagin was reduced and alkylated, it was much more susceptible to hydrolysis by all three proteinases.