Characterization of 4-hydroxyphenylacetate 3-hydroxylase (HpaB) of Escherichia coli as a reduced flavin adenine dinucleotide-utilizing monooxygenase.

ABSTRACT: 4-Hydroxyphenylacetate 3-hydroxylase (HpaB and HpaC) of Escherichia coli W has been reported as a two-component flavin adenine dinucleotide (FAD)-dependent monooxygenase that attacks a broad spectrum of phenolic compounds. However, the function of each component in catalysis is unclear. The large component (HpaB) was demonstrated here to be a reduced FAD (FADH(2))-utilizing monooxygenase. When an E. coli flavin reductase (Fre) having no apparent homology with HpaC was used to generate FADH(2) in vitro, HpaB was able to use FADH(2) and O(2) for the oxidation of 4-hydroxyphenylacetate. HpaB also used chemically produced FADH(2) for 4-hydroxyphenylacetate oxidation, further demonstrating that HpaB is an FADH(2)-utilizing monooxygenase. FADH(2) generated by Fre was rapidly oxidized by O(2) to

SUBMITTER: Xun L 

PROVIDER: S-EPMC91852 | biostudies-literature | 2000 Feb

REPOSITORIES: biostudies-literature