Molting fluid enzymes of the tobacco hornworm, Manduca sexta: Timing of proteolytic and chitinolytic activity in relation to pre‐ecdysial development

Developmental profiles for a number of molting fluid (MF) enzyme activities were established and related to the progress of pupal cuticle degradation during the four days that precede the eclosion of adult tobacco hornworms. Cuticle degrading activity, molting fluid protease 1 (MFP‐1), and molting fluid protease 2 (MFP‐2) all increased in activity at the time that loss of material from the old cuticle occurred. In contrast, chitinase and β‐acetylglucosaminidase activities did not parallel weight loss from the old cuticle. These results are consistent with the hypothesis that proteolytic activity is a prerequisite for the action of chitinase on cuticle chitin.