Function
Involved in the biosynthesis of the parasiticide antibiotic grixazone. Catalyzes the oxidation of 3,4-aminohydroxybenzoate (3,4-AHBOA) to yield the corresponding quinone imine which is then non-enzymatically conjugated with the thiol group of N-acetylcysteine. The resultant compound is oxidized to its quinone imine enzymatically and is then dimerized non-enzymatically with another quinone imine oxidized by GriF to yield grixazone B. 3,4-aminohydroxybenzaldehyde (3,4-AHBAL) can also be used as substrate to yield grixazone A. In the grixazone biosynthetic pathway, it can also function as an o-aminophenol oxidase that catalyzes the formation of the phenoxazinone chromophore from alpha-aminophenol. It can also use 3,4-dihydroxybenzaldehyde, 2-amino-4-methylphenol and 3,4-dihydroxy-L-phenylalanine (L-DOPA) as substrates. In contrast to tyrosinases, it does not display monophenolase activity.
Sequence
MVHVRKNHLTMTAEEKRRFVHAVLEIKRRGIYDRFVKLHIQINSTDYLDKETGKRLGHVNPGFLPWHRQYLLKFEQALQKVDPRVTLPYWDWTTDHGENSPLWSDTFMGGNGRPGDRRVMTGPFARRNGWKLNISVIPEGPEDPALNGNYTHDDRDYLVRDFGTLTPDLPTPQELEQTLDLTVYDCPPWNHTSGGTPPYESFRNHLEGYTKFAWEPRLGKLHGAAHVWTGGHMMYIGSPNDPVFFLNHCMIDRCWALWQARHPDVPHYLPTVPTQDVPDLNTPLGPWHTKTPADLLDHTRFYTYDQ