HYDROXYINDOLES - A NEW CLASS OF LACCASE SUBSTRATES

Hydroxylated indole derivatives (HID) were found to have a very low K( m) with rosemary (Rosmarinus officinalis) laccase (EC 1.10.3.1), and c ould also act as substrates for the laccase of Pyricularia oryzae (wit h the exception of 5-hydroxy-6-methoxyindole), and in some cases with bovine ceruloplasmin. Of the HIDs tested, only 5,6- dihydroxyindole re acted with the catechol oxidase of Solanum tuberosum. The formation of the pigmented products from these reactions could be controlled by th e use of classical laccase inhibitors. It is proposed that this family of compounds may represent useful tools to distinguish between die ac tivities of laccases and catechol oxidases.