Proteolytic enzymes, past and future

Today’s knowledge is based on yesterday’s research, which, for me, started some 60 years ago. In the introduction to this colloquium, the past history of proteolytic enzymes is briefly reviewed against the background of simultaneously developing concepts and methodologies in protein chemistry. This history is followed by a sketch of more recent developments of the role of proteolytic enzymes in physiological regulation and an outlook of future trends apparent from current research.