Differences in fibrinolysis and complement inactivation by venom from different northern blacktailed rattlesnakes (Crotalus molossus molossus).

Venom from 72 different Crotalus molossus molossus rattlesnakes was examined for fibrinolysis and for their ability to inactivate human complement. The fibrinolytic activity of the venoms was variable, but smaller (younger) snakes had less fibrinolytic activity than larger (older) snakes. Major differences between the venoms was detected by isoelectric focusing, and reflected in the number and pI of the proteins with fibrinolytic activity. Of the 72 venoms tested, ten had no effect and three had low activity on complement. The rest of the venoms strongly inactivated complement. The snakes with no activity on complement measured 55 cm or less in length, except for one snake which measured 53 cm and completely inactivated complement. Two larger snakes (76 and 84 cm) had a reduced complement-inactivating activity. Some venoms strongly hydrolyzed C2, whereas others had mild or no effect on this complement component. The attack on C3 was variable: some had no effect on C3, while other venoms produced a 125,000 mol. wt protein, which was recognized by antibodies to C3. Only mild hydrolysis of C4 was evident in serum treated with some venoms. No relationship was evident between the venom properties of this species and geographical distribution. Venom variability is an important clinical reality, and is an important consideration when attempting to isolate proteases from this snake species for further study.