Under aerobic conditions, phenol is usually hydroxylated to catechol and degraded via the meta or ortho pathways. Two types of phenol hydroxylase are known: one is a multi-component enzyme the other is a single-component monooxygenase. This region is found in both types of enzymes [1,2].

1: Complete nucleotide sequence and polypeptide analysis of multicomponent phenol hydroxylase from Pseudomonas sp. strain CF600. Nordlund I, Powlowski J, Shingler V; J Bacteriol 1990;172:6826-6833. PMID:2254258

2: Genetic and functional analysis of the tbc operons for catabolism of alkyl- and chloroaromatic compounds in Burkholderia sp. strain JS150. Kahng HY, Malinverni JC, Majko MM, Kukor JJ; Appl Environ Microbiol 2001;67:4805-4816. PMID:11571188