Protein Expression and Purification, Vol.157, 21-27, 2019
The catalytic domain of cathepsin C (dipeptidyl-peptidase I) alone is a fully functional endoprotease
Cathepsin C is a tetrameric lysosomal protease that acts as a dipeptidyl-peptidase due to the presence of the exclusion domain that is unique among papain-like cysteine proteases. Here we describe a recombinant form of cathepsin C lacking its exclusion domain (CatC Delta Ex) produced in a bacterial expression system (E. coli). CatC Delta Ex is a monomer with endoprotease activity and affinity for hydrophobic residues such as Phe, Leu or Pro, but not Val, in the P2 position. As opposed to cathepsin C, it does not require chloride ions for its activity. Despite lower turnover rates of hydrolysis of synthetic substrates, CatC Delta Ex has elastolytic and gelatinolytic activity comparable to other cysteine cathepsins.