Dipeptidyl peptidase IV (CD 26) and aminopeptidase N (CD 13) catalyzed hydrolysis of cytokines and peptides with N‐terminal cytokine sequences

Abstract

A number of natural cytokines are characterized as having dipeptidyl peptidase (DP) IV susceptible N‐terminal peptide sequences. Here we demonstrate that oligopeptides with sequences analogous to the N‐terminal part of human IL‐1β, IL‐2, TNF‐β and murine IL‐6 were hydrolyzed by purified DP IV and aminopeptidase N (AP‐N). The rate of DP IV‐catalyzed hydrolysis of these peptides was negatively correlated with their chain length. In contrast to these results, no degradation was found under our conditions for the intact recombinant cytokines, IL‐1α, IL‐1β, IL‐2, G‐CSF and for natural IL‐2, independent of whether DP IV and AP‐N were used separately or in combination.