Protease-catalyzed fragment condensation via substrate mimetic strategy: auseful combination of solid-phase peptide synthesis with enzymatic methods

The concept of substrate mimetic strategy represents a new powerful method in the field of enzymatic peptide synthesis. This strategy takes advantage of the shift in the site-specific amino acid moiety from the acyl residue t o the ester-leaving group of the carboxyl component enabling acylation of t he enzyme by nonspecific acyl residues. As a result, peptide bond formation occurs independently of the primary specificity of proteases. Moreover, be cause of the coupling of nonspecific acyl residues, the newly formed peptid e bond is not subject to secondary hydrolysis achieving irreversible peptid e synthesis. Here, we report the combination of solid-phase peptide synthes is with substrate mimetic-mediated enzymatic peptide fragment condensations . First, the utility of the oxime resin strategy for the synthesis of pepti de fragments in the form of substrate mimetics esterified as 4-guanidinophe nyl-, phenyl- and mercaptopropionic acid esters was investigated. The study was completed by using the resulting N-alpha-protected peptide esters as a cyl donors in trypsin-, alpha-chymotrypsin- and V8 protease-catalyzed fragm ent condensations.