Sequence determinants of function and evolution in serine proteases.

Serine proteases of the chymotrypsin family have maintained a common fold over an evolutionary span of more than one billion years. Notwithstanding modest changes in sequence, this class of enzymes has developed a wide variety of substrate specificities and important biological functions such as fibrinolysis, blood coagulation, and complement activation. Recently it has become apparent that the protease domain, especially its C-terminal sequence, accounts fully for this functional diversity and is the most important element in shaping serine protease evolution.