Melanin is an insoluble, unreactive and irregular polymer derived from tyrosine. It is therefore perhaps unreasonable to ask if the melanin of insects is the same product as the melanin of human skin, of animal hair, and the sepia of squid. Biosynthesis of insect melanin, like the others, begins with the oxidation of tyrosine to DOPA (Figure 8.7), which is further oxidized by polyphenol oxidase to dopaquinone (Figure 8.14)

,V^Ycch-cooh dihydroxyphenylalanine l-dopa

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