Chitinase activity during Drosophila development

Before both larval moults in Drosophila melanogaster, the chitin in the cuticle is digested to a significant degree by the moulting fluid. A spurt of chitinase activity appears just before each ecdysis, drops sharply after the first ecdysis, and begins to rise again just about the time that chitin degradation becomes evident. The level of enzyme activity/mg of soluble protein reached just before the second ecdysis is about twice that reached before the first, and this declines gradually after the ecdysis until puparium formation. Chitinase activity is measured with a viscometric assay on a chitosan substrate.The enzyme activity is stable, with no loosely bound cofactor. Data also exist supporting the presence of more than one enzyme fraction in Drosophila with chitinase activity.