When studying proline specific peptidases and basic carboxypeptidases, there often is an overlap between de substrates of these peptidases. Whether a particular substrate is cleaved in vivo by a particular peptidase depends on at least these two parameters:
- the substrate is cleaved efficiently in vitro, and
- substrate and peptidase are in contact in vivo.
Determining substrate specificity of peptidases towards bioactive peptides is a speciality of our lab. Examples are given for carboxypeptidase M (3) and dipeptidyl peptidase 4 (4). Substrate specificity reflects structure-function relationships in the active site of the peptidase (5).