. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. DISTRIBUTION OF DOPA IN INVERTEBRATES 181 Tanned silks Pigmentation of eye > integument Neuroendocnne signals. Sclerotization of egg capsules Figure 1. DOPA and enzymes that metabolize DOPA are phylo- genetically and organismically scattered throughout the invertebrates. This illustration attempts to integrate all reported functions of DOPA chemistry in a single fantastical chimaera. See text and Table I for specific details. crete a catechol oxidase into their meals to detoxify plant tissues rich in phenols (Peng and Mil
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. DISTRIBUTION OF DOPA IN INVERTEBRATES 181 Tanned silks Pigmentation of eye > integument Neuroendocnne signals. Sclerotization of egg capsules Figure 1. DOPA and enzymes that metabolize DOPA are phylo- genetically and organismically scattered throughout the invertebrates. This illustration attempts to integrate all reported functions of DOPA chemistry in a single fantastical chimaera. See text and Table I for specific details. crete a catechol oxidase into their meals to detoxify plant tissues rich in phenols (Peng and Miles, 1988). DOPA and related metabolites in plants and seeds pose an effec- tive chemical barrier against many herbivores lacking in such salivary activity (Rehr el al., 1973). Insects (Nappi ct 1991), crustaceans (Johansson and Soderhall, 1988), holothuroids (Canicatti and Seymour, 1991), molluscs (Belyayeva, 1981), annelids (Valembois el al. 1988), and tunicates (Walters et al., 1992) have type II enzyme ac- tivity in body fluids, where it functions in a cell-mediated immunity leading to the encapsulation of foreign material and often the repair of injured tissue. In arthropods, the enzyme is present as a zymogen and activated by a patho- gen-sensitive protease (Aspan and Soderhall, 1991). Both monophenol monoxygenase and catechol oxidase activ- ities are present in arthropods, while in ascidians and hol- othuroids only catechol oxidase is detectable (Canicatti and Seymour, 1991; Walters et 1992). There are very few data on the molecular kinetics of these enzymes, and fewer still on the identity of the physiological substrates of such enzymes. Nappi et al. (1991) observed that blood tyrosine levels increased during parasite infection ofDro- sophila melanogaster. and tyrosine would be an appro- priate substrate if melanin production were the chief aim of the enzyme. Perhaps the DOPA-containing peptides of morula cells (Dorsett et 1987; Azumi et 1990; Smith e
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