- Cathepsin B-labile dipeptide linkers for lysosomal release of doxorubicin from internalizing immunoconjugates: model studies of enzymatic drug release and antigen-specific in vitro anticancer activity. Dubowchik, G.M., Firestone, R.A., Padilla, L., Willner, D., Hofstead, S.J., Mosure, K., Knipe, J.O., Lasch, S.J., Trail, P.A. Bioconjug. Chem. (2002)