Abstract: A cDNA molecule encoding for a particular 33 kD cysteine proteinase derived from maize is provided. When expressed in a plant, particularly corn or cotton, the protein provides insect resistance to the plant, and when expressed in the anther, the 33 kD cysteine proteinase provides sterility in the male of the plant species. The cDNA molecule can also be used as a probe to isolate suitable promoters for regulating expression of a 33 kD cysteine proteinase in callus or to provide a transformed baculovirus, which confers insect resistance upon a plant when the plant is infectted with the transformed baculovirus. Additionally, a DNA sequence of 264 base pairs in length is provided that provides enhanced enzymatic/catalytic activity in proteins expressed when the 264 base pair sequence is operably linked to a DNA molecule encoding for a cysteine proteinase.