these findings show that the mr 52000 human plasminogen activator exists in a proenzyme form consisting of a single polypeptide chain that by proteolysis between half-cystine residues is converted into the active enzyme consisting of two chains with molecular weights of approximately 20000 and 32000 , the active site being on the latter chain .
C0032144
plasminogen activator
C0597304
proteolysis