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Activation of recombinant proenteropeptidase by duodenase
T S Zamolodchikova1, E A Sokolova, D Lu
1Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, Moscow, Russia. tatyana@enzyme.siobc.ras.ru
Abstract:
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 (kcat/Km = 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.