A.H. Warner, C. Matheson-1998
Comparative Biochemistry and Physiology B. Biochemistry and Molecular Biology, 119 (2): 255-263 (from Current Contents)
Abstract:
In arthropods, molting is required in order for the organism to escape periodically from its exoskeleton (cuticle) to undergo metamorphosis, growth, or reproduction. During molting the cuticle is first released from the epidermis (apolysis) then degraded (ecdysis). This involves a complex set of hydrolases secreted into the exuviate under control of ecdysteroids and several environmental factors. During the first two larval moles in the brine shrimp, Artemia franciscana, large amounts of two serine proteases appear in the incubation medium, concomitant with N-acetyl-beta-D-glucosaminidase, a well-described chitin degrading enzyme. These proteases were analyzed by gel filtration, fast protein liquid chromatography (FPLC), electrophoresis on gelatin polyacrylamide gels, and with various inhibitors, and found to be nearly identical to two serine proteases synthesized during early larval development in Artemia and thought to be digestive enzymes. The appearance or secretion of these serine proteases into the incubation medium during larval development is required for apolysis and ecdysis, and appears to be dependent on cysteine protease activity in the epidermal layer under the cuticle.
(Univ. Windsor, Dept. Biol. Sci., Windsor ON N9B 3P4, Canada)