Activation of plasma prekallikrein and inactive renin by puff adder venom

The activation of inactive renin during incubation of human plasma with puff adder venom at pH 7.4 was found to be a complex process. Gel filtration on Sephacryl S-200 indicated that the venom contains a major peak of caseinolytic and renin-activating activity of low molecular weight. This enzyme was a metalloproteinase. During incubation with plasma the metalloproteinase formed a complex with alpha 2-macroglobulin and retained caseinolytic and reninactivation activity. Venom metalloproteinase activated prekallikrein, but not plasmin, and plasms kallikrein may account for at least part of the activation of inactive renin observed.