UniProt functional annotation for Q6Q272



	UniProt functional annotation for Q6Q272

UniProt code: Q6Q272.

Organism: Acinetobacter baumannii.

Taxonomy: Bacteria; Proteobacteria; Gammaproteobacteria; Pseudomonadales; Moraxellaceae; Acinetobacter; Acinetobacter calcoaceticus/baumannii complex.

Function: Oxygenase component of a two-component system that utilizes reduced FMN (FMNH2) supplied by the reductase component to catalyze the hydroxylation of 4-hydroxyphenylacetic acid, leading to the production of 3,4-dihydroxyphenylacetate (3,4-DHPA). Also utilizes other reduced flavins such as FADH2 and reduced riboflavin to a lesser extent. Only the compounds with a hydroxyl group in the para (p-) position can be hydroxylated. May also oxidize phenol to catechol, and hydroxylate other phenol derivatives. {ECO:0000269|PubMed:11683878, ECO:0000269|PubMed:15451173, ECO:0000269|PubMed:16042421, ECO:0000269|PubMed:16627482, ECO:0000269|PubMed:17595116, ECO:0000269|PubMed:21030590}.

Catalytic activity: Reaction=4-hydroxyphenylacetate + FMNH2 + O2 = 3,4- dihydroxyphenylacetate + FMN + H(+) + H2O; Xref=Rhea:RHEA:59880, ChEBI:CHEBI:15377, ChEBI:CHEBI:15378, ChEBI:CHEBI:15379, ChEBI:CHEBI:17612, ChEBI:CHEBI:48999, ChEBI:CHEBI:57618, ChEBI:CHEBI:58210; Evidence={ECO:0000269|PubMed:11683878, ECO:0000269|PubMed:15451173, ECO:0000269|PubMed:16627482};

Catalytic activity: Reaction=4-hydroxyphenylacetate + FADH2 + O2 = 3,4- dihydroxyphenylacetate + FAD + H(+) + H2O; Xref=Rhea:RHEA:30595, ChEBI:CHEBI:15377, ChEBI:CHEBI:15378, ChEBI:CHEBI:15379, ChEBI:CHEBI:17612, ChEBI:CHEBI:48999, ChEBI:CHEBI:57692, ChEBI:CHEBI:58307; EC=1.14.14.9; Evidence={ECO:0000269|PubMed:11683878, ECO:0000269|PubMed:15451173, ECO:0000269|PubMed:16627482};

Activity regulation: Inhibited by flavin concentrations greater than 15 uM. Also inhibited by excess p-hydroxyphenylacetate (HPA). {ECO:0000269|PubMed:11683878, ECO:0000269|PubMed:16042421, ECO:0000269|PubMed:17595116}.

Biophysicochemical properties: Kinetic parameters: KM=19 uM for 4-hydroxyphenylacetate (with FMN as cosubstrate) {ECO:0000269|PubMed:11683878}; KM=14 uM for 4-hydroxyphenylacetate (with FAD as cosubstrate) {ECO:0000269|PubMed:11683878}; KM=25 uM for 4-hydroxyphenylacetate (with FMN as cosubstrate) {ECO:0000269|PubMed:15451173}; KM=15 uM for 4-hydroxyphenylacetate (with FAD as cosubstrate) {ECO:0000269|PubMed:15451173}; Note=Km values measured using the C1-C2 complex.; pH dependence: Optimum pH is 6-10. {ECO:0000269|PubMed:21030590};

Pathway: Aromatic compound metabolism; 4-hydroxyphenylacetate degradation; pyruvate and succinate semialdehyde from 4- hydroxyphenylacetate: step 1/7. {ECO:0000269|PubMed:11683878}.

Subunit: Homotetramer. The p-hydroxyphenylacetate 3-hydroxylase (HpaH) is composed of an oxygenase component C2 and a reductase component C1. {ECO:0000269|PubMed:11683878, ECO:0000269|PubMed:17227849}.

Similarity: Belongs to the HpaH/HsaA monooxygenase family. {ECO:0000305}.

Annotations taken from UniProtKB at the EBI.


Organism:		Acinetobacter baumannii.
Taxonomy:		Bacteria; Proteobacteria; Gammaproteobacteria; Pseudomonadales; Moraxellaceae; Acinetobacter; Acinetobacter calcoaceticus/baumannii complex.



Function:		Oxygenase component of a two-component system that utilizes reduced FMN (FMNH2) supplied by the reductase component to catalyze the hydroxylation of 4-hydroxyphenylacetic acid, leading to the production of 3,4-dihydroxyphenylacetate (3,4-DHPA). Also utilizes other reduced flavins such as FADH2 and reduced riboflavin to a lesser extent. Only the compounds with a hydroxyl group in the para (p-) position can be hydroxylated. May also oxidize phenol to catechol, and hydroxylate other phenol derivatives. {ECO:0000269\|PubMed:11683878, ECO:0000269\|PubMed:15451173, ECO:0000269\|PubMed:16042421, ECO:0000269\|PubMed:16627482, ECO:0000269\|PubMed:17595116, ECO:0000269\|PubMed:21030590}.


Catalytic activity:		Reaction=4-hydroxyphenylacetate + FMNH2 + O2 = 3,4- dihydroxyphenylacetate + FMN + H(+) + H2O; Xref=Rhea:RHEA:59880, ChEBI:CHEBI:15377, ChEBI:CHEBI:15378, ChEBI:CHEBI:15379, ChEBI:CHEBI:17612, ChEBI:CHEBI:48999, ChEBI:CHEBI:57618, ChEBI:CHEBI:58210; Evidence={ECO:0000269\|PubMed:11683878, ECO:0000269\|PubMed:15451173, ECO:0000269\|PubMed:16627482};
Catalytic activity:		Reaction=4-hydroxyphenylacetate + FADH2 + O2 = 3,4- dihydroxyphenylacetate + FAD + H(+) + H2O; Xref=Rhea:RHEA:30595, ChEBI:CHEBI:15377, ChEBI:CHEBI:15378, ChEBI:CHEBI:15379, ChEBI:CHEBI:17612, ChEBI:CHEBI:48999, ChEBI:CHEBI:57692, ChEBI:CHEBI:58307; EC=1.14.14.9; Evidence={ECO:0000269\|PubMed:11683878, ECO:0000269\|PubMed:15451173, ECO:0000269\|PubMed:16627482};
Activity regulation:		Inhibited by flavin concentrations greater than 15 uM. Also inhibited by excess p-hydroxyphenylacetate (HPA). {ECO:0000269\|PubMed:11683878, ECO:0000269\|PubMed:16042421, ECO:0000269\|PubMed:17595116}.
Biophysicochemical properties:		Kinetic parameters: KM=19 uM for 4-hydroxyphenylacetate (with FMN as cosubstrate) {ECO:0000269\|PubMed:11683878}; KM=14 uM for 4-hydroxyphenylacetate (with FAD as cosubstrate) {ECO:0000269\|PubMed:11683878}; KM=25 uM for 4-hydroxyphenylacetate (with FMN as cosubstrate) {ECO:0000269\|PubMed:15451173}; KM=15 uM for 4-hydroxyphenylacetate (with FAD as cosubstrate) {ECO:0000269\|PubMed:15451173}; Note=Km values measured using the C1-C2 complex.; pH dependence: Optimum pH is 6-10. {ECO:0000269\|PubMed:21030590};
Pathway:		Aromatic compound metabolism; 4-hydroxyphenylacetate degradation; pyruvate and succinate semialdehyde from 4- hydroxyphenylacetate: step 1/7. {ECO:0000269\|PubMed:11683878}.
Subunit:		Homotetramer. The p-hydroxyphenylacetate 3-hydroxylase (HpaH) is composed of an oxygenase component C2 and a reductase component C1. {ECO:0000269\|PubMed:11683878, ECO:0000269\|PubMed:17227849}.
Similarity:		Belongs to the HpaH/HsaA monooxygenase family. {ECO:0000305}.