HUMAN PROGELATINASE-A CAN BE ACTIVATED BY MATRILYSIN

The activation of human progelatinase A by other matrix metalloprotein ases was studied by following both the loss of its N-terminal propepti de and the accompanying increase in the rate of hydrolysis of a synthe tic substrate. Activated stromelysin 1 was unable to cause any activat ion of progelatinase A beyond that slowly occuring by autolysis, but a n 8 h incubation with activated matrilysin was able to produce 64% of the activity generated by incubation with (4-aminophenylmercuric)aceta te (APMA). Wild-type progelatinase A and a mutant proenzyme that canno t become active were both cleaved by matrilysin to a lower molecular w eight species that had lost the propeptide. This shows that matrilysin activates progelatinase A by removing the propeptide in a process tha t does not require any autolytic cleavages.