... Differences in substrate specificities between cysteine protease CPB isoforms of Leishmania mexicana are mediated by a few amino acid changes Maria A. Juliano1, Darren R. Brooks2, Paul ... rapidly removed by a signal peptidase upon transfer into the endoplasmic reticu-lum ,a1 06aminoacidpro-region ,a2 18aminoacidmaturedomain that includes the active site, and a C-terminaldomain of ... 100 amino acids [7]. The first twogenes of t he array, CPB1 and CPB2 , are atypical becausethey encode enzymes with a C-terminal domain of just 16 amino a cids [7]. Furthermore, CPB1 and CPB2 are expressed...