Activation of recombinant proenteropeptidase by duodenase

Duodenase, a serine proteinase from bovine Brunner's (duodenal) glands that was predicted to be a natural activator of enteropeptidase zymogen, cleaves and activates recombinant single-chain bovine proenteropeptidase (k(cat)/K-m = 2700 M-1 s(-1)). The measured rate of proenteropeptidase cleavage by duodenase was about 70-fold lower compared with the rate of trypsin-mediated cleavage of the zymogen, The role of duodenase is supposed to be the primary activator of proenteropeptidase maintaining a certain level of active enteropeptidase in the duodenum, A new scheme of proteolytic activation cascade of digestive proteases is discussed. (C) 2000 Federation of European Biochemical Societies.