Several other inhibitors were also isolated and characterised to various extent. The kinetics of interaction of cysteine proteinases with their inhibitors are being studied by stopped-flow technique. Cloning and mutation studies of proteinase inhibitors along with computer modelling are being carried out. Because of their important role cysteine proteinases and their inhibitors are being studied also in various pathological conditions as e.g. cancer and rheumatoid arthritis. Proteinase inhibitors in various plants are being investigated as they play an important role in natural plant defence mechanism against insects and pests.
Special attention is focused on potato.
An inhibitor of aspartic and an inhibitor of cysteine proteinases were isolated from potato tubers and sequenced. All these proteins were sequenced in protein, cDNA and gene level. The expression of these toxins in the form of inactive precursors and subsequent reactivation enabled site directed mutagenesis studies of toxic site. Bovine stefin C, a new member of the stefin family. Stefins and lysosomal cathepsins B, L and D in human breast carcinoma.