Antonio Piga
3-Hydroxykynurenine as a substrate/activator for mushroom tyrosinase
SANJUST, ENRICO;CURRELI, NICOLETTA;RESCIGNO, ANTONIO
2003-01-01
Abstract
3-Hydroxykynurenine is a tryptophan metabolite with an o-aminophenol structure. It is both a tyrosinase activator and a substrate, reducing the lag phase, stimulating the monophenolase activity, and being oxidized to xanthommatin. In the early stage of monophenol hydroxylation, catechol accumulation takes place, whereas 3-hydroxykynurenine is substantially unchanged and no significant amounts of the o-quinone are produced. These results suggest an activating action of 3-hydroxykynurenine toward o-hydroxylation of monophenols. 3-Hydroxykynurenine could therefore well act as a physiological device to control phenolics metabolism to catechols and quinonoids. (C) 2003 Elsevier Science (USA). All rights reserved.Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.