PROTEASE-CATALYZED PEPTIDE-SYNTHESIS - BASIC PRINCIPLES, NEW SYNTHESIS STRATEGIES AND MEDIUM ENGINEERING

The application of enzymes to perform selective transformations is the central aim of industrial biocatalysis. Since a simple handled C-N li gase is not available, the only alternative of general practical inter est for enzymatic peptide bond formation are proteases due to the prin ciple of microscopic reversibility. The stereo- and regiospecificity o f proteases, which guarantee racemization-free segment condensation an d require only minimal side-chain protection, are significant for prep arative purposes. Unfortunately, proteases are not perfect acyltransfe rases. Both unwanted proteolytic side reactions and the hydrolysis of the acyl-enzyme in the kinetic approach are the major problems in enzy matic peptide synthesis. The object of this paper was to demonstrate s everal new synthesis strategies including medium engineering that enab les one to bypass unfavorable reaction routes. Planning and optimizati on of enzymatic peptide synthesis require the S' subsite mapping of pr oteases and the knowledge of additional basic parameters that determin e the reaction course.