Cocoonase is a trypsin-like[1] proteolytic enzyme[2] produced by silkworms (of both Bombyx,[3] Heliconius[4] and Antheraea[5][6] species) as they near the final stages of their metamorphosis. It is produced by cells in the proboscis[7] and exuded onto the galeae.[8] Its function is to weaken the fibers of the cocoon, thereby facilitating the emergence of the adult insect.
It was discovered by Carroll Williams.[9]