Abstract: | Melanin from Sepia officinalis is a natural polymer containing many carboxylic groups. It is present in the ink sac of the animal as the Mg and Ca salt. Purified sepiomelanin is able to combine with cations and, to a less extent with anions; by heating CO2 is evolved. A formula closely related to ... [---C8H5O2N---C8H4O2N·COOH---]x... is suggested for sepiomelanin and its derivatives. Owing to the presence of a tyrosinase in the ink sack it is possible that 2-carboxy-2,3-dihydroindole-5,6-quinone (dopachrome) plays an important part in the biological process of polymerization. |