The proteinases are a major group of hydrolytic enzymes in insects and are involved in digestive processes, proenzyme activation, liberation of physiologically active peptides, complement activation, and inflammation processes amongst others .The proteinases are classified according to their mechanism of catalysis: (1) serine proteinases; (2) cysteine proteinases; (3) aspartic proteinases, and (4) metalloproteinases.
For an efficient management of pest control through proteinase inhibitor transgenes, it is Imperative to know the type of enzymes present in the gut of insects and pests. The two major proteinase classes in the digestive systems of phytophagous insects are the serine and cysteine proteinases