1.14.14.9: 4-hydroxyphenylacetate 3-monooxygenase
This is an abbreviated version!
For detailed information about 4-hydroxyphenylacetate 3-monooxygenase, go to the full flat file.
Word Map on EC 1.14.14.9
-
1.14.14.9
-
flavin
-
3,4-dihydroxyphenylacetate
-
baumannii
-
flavin-dependent
-
tyrosol
-
hydroxytyrosol
-
fmnh
-
two-protein
-
piceatannol
-
synthesis
- 1.14.14.9
- flavin
- 3,4-dihydroxyphenylacetate
- baumannii
-
flavin-dependent
- tyrosol
- hydroxytyrosol
- fmnh
-
two-protein
- piceatannol
- synthesis
Reaction
Synonyms
4 HPA 3-hydroxyylase, 4-HPA hydroxylase, 4-hydroxyphenylacetate 3-hydroxylase, 4-hydroxyphenylacetic acid 3-hydroxylase, 4HPA 3-monooxygenase, 4HPA3H, C2-hpah, EC 1.14.13.3, HPA 3-hydroxylase, HpaB, hpaBC, HpaC, HPAH, More, p-hydroxyphenylacetate 3-hydroxylase, p-hydroxyphenylacetate hydroxylase, p-hydroxyphenylacetic 3-hydroxylase, TPY_2462, two-component p-hydroxyphenylacetate hydroxylase
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Substrates Products
Substrates Products on EC 1.14.14.9 - 4-hydroxyphenylacetate 3-monooxygenase
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REACTION DIAGRAM
2,5-dihydroxyphenylacetate + ?
?
-
155% of 4-hydroxyphenylacetate activity
-
-
?
2-phenylbutyric acid + H2
?
-
86% of 4-hydroxyphenylacetate activity
-
-
?
2-phenylpropionic acid + ?
?
-
77% of 4-hydroxyphenylacetate activity
-
-
?
3,4-dihydroxybenzoate + ?
?
-
30% of 4-hydroxyphenylacetate activity
-
-
?
3,4-dihydroxyphenylacetate + FAD + H2O
4-hydroxyphenylacetate + FADH2 + O2
-
-
-
-
r
3-(3,4-dihydroxyphenyl)-propanoic acid + FADH2 + O2
3-(3,4,5-trihydroxyphenyl)-propanoic acid + FAD + H2O
low activity
-
-
?
3-(4-hydroxyphenyl)-propanoic acid + FADH2 + O2
3-(3,4-dihydroxyphenyl)-propanoic acid + FAD + H2O
-
-
-
?
3-hydroxyphenylacetate + NADH + H+ + O2
3,4-hydroxyphenylacetate + NAD+ + H2O
-
-
-
-
?
4-aminophenylacetate + FMNH2 + O2
4-amino-3,5-dihydroxyphenylacetate + FMN + H2O
-
-
-
?
4-bromophenol + NADH + H+ + O2
4-bromocatechol + NAD+ + H2O
rate of halophenol consumption 2.9 microM/min/g cell dry weight
-
-
?
4-chlorophenol + NADH + H+ + O2
4-chlorocatechol + NAD+ + H2O
rate of halophenol consumption 3.3 microM/min/g cell dry weight
-
-
?
4-fluorophenol + NADH + H+ + O2
4-fluorocatechol + NAD+ + H2O
rate of halophenol consumption 5.3 microM/min/g cell dry weight
-
-
?
4-fluorophenylacetate + NADH + O2
4-fluoro-3-hydroxyphenylacetate + NAD+ + H2O
-
-
-
?
4-hydroxybenzoate + ?
3,4-dihydroxybenzoate + ?
-
15% of 4-hydroxyphenylacetate activity
-
?
4-hydroxyphenylacetate + FMNH2 + O2
3,4-dihydroxyphenylacetate + FMN + H2O
-
-
-
-
?
4-iodophenol + NADH + H+ + O2
4-iodocatechol + NAD+ + H2O
rate of halophenol consumption 1.7 microM/min/g cell dry weight
-
-
?
caffeic acid + FADH2 + O2
3,4,5-trihydroxycinnamic acid + FAD + H2O
-
-
-
?
coniferaldehyde + FADH2 + O2
5-hydroxyconiferaldehyde + FAD + H2O
-
-
-
?
ferulic acid + FADH2 + O2
5-hydroxyferulic acid + FAD + H2O
-
-
-
?
L-(3,4-dihydroxy)phenylalanine + ?
?
-
10% of 4-hydroxyphenylacetate
-
?
L-tyrosine + ?
L-(3,4-dihydroxy)phenylalanine + ?
-
8% of 4-hydroxyphenylacetate activity
-
?
octopamine + FMNH + O2
norepinephrine + FMN + H2O
no substrate of wild-type or mutant R263E, R263D, R263A, but substrate of mutant R263D/Y398D
-
-
?
p-coumaric acid + FADH2 + O2
caffeic acid + FAD + H2O
-
-
-
?
tyramine + FMNH + O2
dopamine + FMN + H2O
no substrate of wild-type or mutant R263E, but substrate of mutants R263D and R263A
-
-
?
3,4-dihydroxyphenylacetate + ?
?
-
50% of 4-hydroxyphenylacetate activity
-
-
?
3-(3,4-dihydroxy)phenylpropionate + ?
-
-
-
?
3-(4-hydroxyphenyl)propionate + ?
3-(3,4-dihydroxy)phenylpropionate + ?
-
-
-
?
3-(4-hydroxyphenyl)propionate + ?
3-(3,4-dihydroxy)phenylpropionate + ?
-
83% of 4-hydroxyphenylacetate activity
-
?
3,4-hydroxyphenylacetate + FMN + H2O
-
hydroxylation rate constant is 16 per s and the product conversion ratio is 90%
-
?
3-hydroxyphenylacetate + FMNH2 + O2
3,4-hydroxyphenylacetate + FMN + H2O
-
-
-
-
?
3,4-hydroxyphenylacetate + NAD(P)+ + H2O
-
98% of 4-hydroxyphenylacetate activity
-
-
?
3-hydroxyphenylacetate + NAD(P)H + O2
3,4-hydroxyphenylacetate + NAD(P)+ + H2O
-
-
-
?
3-hydroxyphenylacetate + NAD(P)H + O2
3,4-hydroxyphenylacetate + NAD(P)+ + H2O
-
-
-
?
3,4-hydroxyphenylacetate + NAD+ + H2O
-
82% activity of 4-hydroxyphenylacetate
-
?
3-hydroxyphenylacetate + NADH + O2
3,4-hydroxyphenylacetate + NAD+ + H2O
-
-
-
?
3-hydroxyphenylacetate + NADH + O2
3,4-hydroxyphenylacetate + NAD+ + H2O
-
-
-
?
4-amino-3-hydroxyphenylacetate + ?
-
-
-
?
4-aminophenylacetate + ?
4-amino-3-hydroxyphenylacetate + ?
-
-
-
?
4-coumaric acid + FADH2 + O2
caffeic acid + FAD + H2O
-
-
-
?
3,4-dihydroxyphenylacetate + FAD + H2O
-
-
-
-
?
4-hydroxyphenylacetate + FADH2 + O2
3,4-dihydroxyphenylacetate + FAD + H2O
-
-
-
-
?
4-hydroxyphenylacetate + FADH2 + O2
3,4-dihydroxyphenylacetate + FAD + H2O
-
-
-
-
?
4-hydroxyphenylacetate + FADH2 + O2
3,4-dihydroxyphenylacetate + FAD + H2O
-
-
-
?
4-hydroxyphenylacetate + FADH2 + O2
3,4-dihydroxyphenylacetate + FAD + H2O
-
4.3 mM 4-hydroxyphenylacetate is converted within 1 h
-
-
?
3,4-dihydroxyphenylacetate + FMN + H2O
-
-
-
?
4-hydroxyphenylacetate + FMNH + O2
3,4-dihydroxyphenylacetate + FMN + H2O
-
-
-
-
?
4-hydroxyphenylacetate + FMNH + O2
3,4-dihydroxyphenylacetate + FMN + H2O
Thermus thermophilus HB8 / ATCC 27634 / DSM 579
-
-
-
-
?
3,4-dihydroxyphenylacetate + NAD(P)+ + H2O
-
-
-
?
4-hydroxyphenylacetate + NAD(P)H + H+ + O2
3,4-dihydroxyphenylacetate + NAD(P)+ + H2O
-
-
-
-
?
4-hydroxyphenylacetate + NAD(P)H + H+ + O2
3,4-dihydroxyphenylacetate + NAD(P)+ + H2O
4-hydroxyphenylacetate, FAD, NADH, and O2 binding structures, overview, the binding and dissociation of flavin are accompanied by conformational changes of the loop between beta5 and beta6 and of the loop between beta8 and beta9, leading to preformation of part of the substrate-binding site involving Ser197 and Thr198. The latter loop further changes its conformation upon binding of 4-hydroxyphenylacetate and obstructs the active site from the bulk solvent. Arg100 is located adjacent to the putative oxygen-binding site and may be involved in the formation and stabilization of the C4a-hydroperoxyflavin intermediate
-
-
?
4-hydroxyphenylacetate + NAD(P)H + H+ + O2
3,4-dihydroxyphenylacetate + NAD(P)+ + H2O
-
FAD and NAD+ are bound in the groove in the extended and folded conformation, respectively, structure, overview
-
-
?
4-hydroxyphenylacetate + NAD(P)H + H+ + O2
3,4-dihydroxyphenylacetate + NAD(P)+ + H2O
Thermus thermophilus HB8 / ATCC 27634 / DSM 579
-
-
-
?
4-hydroxyphenylacetate + NAD(P)H + H+ + O2
3,4-dihydroxyphenylacetate + NAD(P)+ + H2O
Thermus thermophilus HB8 / ATCC 27634 / DSM 579
4-hydroxyphenylacetate, FAD, NADH, and O2 binding structures, overview, the binding and dissociation of flavin are accompanied by conformational changes of the loop between beta5 and beta6 and of the loop between beta8 and beta9, leading to preformation of part of the substrate-binding site involving Ser197 and Thr198. The latter loop further changes its conformation upon binding of 4-hydroxyphenylacetate and obstructs the active site from the bulk solvent. Arg100 is located adjacent to the putative oxygen-binding site and may be involved in the formation and stabilization of the C4a-hydroperoxyflavin intermediate
-
-
?
4-hydroxyphenylacetate + NAD(P)H + H+ + O2
3,4-dihydroxyphenylacetate + NAD(P)+ + H2O
Thermus thermophilus HB8 / ATCC 27634 / DSM 579
-
-
-
-
?
4-hydroxyphenylacetate + NAD(P)H + H+ + O2
3,4-dihydroxyphenylacetate + NAD(P)+ + H2O
Thermus thermophilus HB8 / ATCC 27634 / DSM 579
-
FAD and NAD+ are bound in the groove in the extended and folded conformation, respectively, structure, overview
-
-
?
3,4-dihydroxyphenylacetate + NAD(P)+ + H2O
-
enzyme is induced by 4-hydroxyphenylacetate, no constitutive synthesis
-
ir
4-hydroxyphenylacetate + NAD(P)H + O2
3,4-dihydroxyphenylacetate + NAD(P)+ + H2O
-
enzyme is induced by 4-hydroxyphenylacetate, no constitutive synthesis
-
ir
3,4-dihydroxyphenylacetate + NAD+ + H2O
-
-
-
-
?
4-hydroxyphenylacetate + NADH + H+ + O2
3,4-dihydroxyphenylacetate + NAD+ + H2O
-
-
-
?
4-hydroxyphenylacetate + NADH + H+ + O2
3,4-dihydroxyphenylacetate + NAD+ + H2O
-
HPAH is composed of two proteins: a FMN reductase C1 and an oxygenase C2, C1 catalyzes the reduction of FMN by NADH to generate reduced FMN, FMNH2, for use by C2 in the hydroxylation reaction, C1 is unique among the flavin reductases in that the substrate 4-hydroxyphenylacetate stimulates the rates of both the reduction of FMN and release of FMNH2 from the enzyme, the dissociation of FMNH2 from C1 is rate-limiting in the intermolecular transfer of FMNH2 from C1 to C2, and this process is regulated by the presence of 4-hydroxyphenylacetate , overview
-
-
?
4-hydroxyphenylacetate + NADH + H+ + O2
3,4-dihydroxyphenylacetate + NAD+ + H2O
substrate binding, catalytic mechanism and structure-function relationship, overview
-
-
?
4-hydroxyphenylacetate + NADH + H+ + O2
3,4-dihydroxyphenylacetate + NAD+ + H2O
via C2-FMNH-, and C4a-hydroperoxy-FMN and C4a-hydroxy-FMN
-
-
?
4-hydroxyphenylacetate + NADH + H+ + O2
3,4-dihydroxyphenylacetate + NAD+ + H2O
-
-
-
?
4-hydroxyphenylacetate + NADH + H+ + O2
3,4-dihydroxyphenylacetate + NAD+ + H2O
compared with intracellular cell extracts, the purified recombinant HpaH protein does not display detectable activity toward the 4-hydroxyphenylacetate substrate under the assay conditions used, in contrast to the cell extract, overview
-
-
?
4-hydroxyphenylacetate + NADH + H+ + O2
3,4-dihydroxyphenylacetate + NAD+ + H2O
-
-
-
?
4-hydroxyphenylacetate + NADH + H+ + O2
3,4-dihydroxyphenylacetate + NAD+ + H2O
compared with intracellular cell extracts, the purified recombinant HpaH protein does not display detectable activity toward the 4-hydroxyphenylacetate substrate under the assay conditions used, in contrast to the cell extract, overview
-
-
?
4-hydroxyphenylacetate + NADH + H+ + O2
3,4-dihydroxyphenylacetate + NAD+ + H2O
-
-
-
-
?
4-hydroxyphenylacetate + NADH + H+ + O2
3,4-dihydroxyphenylacetate + NAD+ + H2O
-
-
-
-
?
4-hydroxyphenylacetate + NADH + H+ + O2
3,4-dihydroxyphenylacetate + NAD+ + H2O
-
-
-
?
4-hydroxyphenylacetate + NADH + H+ + O2
3,4-dihydroxyphenylacetate + NAD+ + H2O
Thermus thermophilus HB8 / ATCC 27634 / DSM 579
-
-
-
?
3,4-dihydroxyphenylacetate + NAD+ + H2O
-
-
-
?
4-hydroxyphenylacetate + NADH + O2
3,4-dihydroxyphenylacetate + NAD+ + H2O
-
-
-
?
4-hydroxyphenylacetate + NADH + O2
3,4-dihydroxyphenylacetate + NAD+ + H2O
-
-
-
?
4-hydroxyphenylacetate + NADH + O2
3,4-dihydroxyphenylacetate + NAD+ + H2O
-
high substrate specificity
-
-
?
4-hydroxyphenylacetate + NADH + O2
3,4-dihydroxyphenylacetate + NAD+ + H2O
-
biodegradation of aromatic compounds
-
?
4-hydroxyphenylacetate + NADH + O2
3,4-dihydroxyphenylacetate + NAD+ + H2O
-
high substrate specificity, reduction of enzyme reductase component C1 by NADH occurs in two phases, while in the presence of HPA, the reduction of C1 by NADH occurs in a single phase requiring complex formation of C1 and 4-hydroxyphenylacetate prior to binding of NADH, C1 is specifically reduced by the pro-(S)-hydride, the reaction of reduced C1 with oxygen, the reoxidation reaction is also biphasic, consistent with reduced C1 being a mixture of fast and slow reacting species, rate constants for both phases are the same in the absence and presence of HPA, but in the presence of HPA, the equilibrium shifts toward the faster reacting species
-
-
?
4-hydroxyphenylacetate + NADH + O2
3,4-dihydroxyphenylacetate + NAD+ + H2O
-
hydroxylation occurs from the ternary complex forming the C2-C(4a)-hydroxy-FMN-3,4-dihydroxyphenylacetate complex
-
-
?
4-hydroxyphenylacetate + NADH + O2
3,4-dihydroxyphenylacetate + NAD+ + H2O
-
-
-
?
4-hydroxyphenylacetate + NADH + O2
3,4-dihydroxyphenylacetate + NAD+ + H2O
-
enzyme is induced by 4-hydroxyphenylacetate, no constitutive synthesis
-
ir
4-hydroxyphenylacetate + NADH + O2
3,4-dihydroxyphenylacetate + NAD+ + H2O
-
-
-
?
4-hydroxyphenylacetate + NADH + O2
3,4-dihydroxyphenylacetate + NAD+ + H2O
-
enzyme is induced by 4-hydroxyphenylacetate, no constitutive synthesis
-
ir
4-hydroxyphenylacetate + NADH + O2
3,4-dihydroxyphenylacetate + NAD+ + H2O
-
degradation of tyrosine with 3,4-dihydroxyphenylacetate as key intermediate
-
?
4-hydroxyphenylacetate + NADH + O2
3,4-dihydroxyphenylacetate + NAD+ + H2O
-
degradation of tyrosine with 3,4-dihydroxyphenylacetate as key intermediate
-
?
4-hydroxyphenylacetate + NADH + O2
3,4-dihydroxyphenylacetate + NAD+ + H2O
-
-
-
?
4-hydroxyphenylacetate + NADH + O2
3,4-dihydroxyphenylacetate + NAD+ + H2O
-
-
-
?
4-hydroxyphenylacetate + NADH + O2
3,4-dihydroxyphenylacetate + NAD+ + H2O
-
-
-
?
4-hydroxyphenylacetate + NADH + O2
3,4-dihydroxyphenylacetate + NAD+ + H2O
-
-
-
?
4-hydroxyphenylacetate + NADH + O2
3,4-dihydroxyphenylacetate + NAD+ + H2O
-
-
-
-
?
4-hydroxyphenylacetate + NADH + O2
3,4-dihydroxyphenylacetate + NAD+ + H2O
-
O2 can be replaced by FADH
-
?
4-hydroxyphenylacetate + NADH + O2
3,4-dihydroxyphenylacetate + NAD+ + H2O
-
enzyme is induced by 4-hydroxyphenylacetate, no constitutive synthesis
-
ir
4-hydroxyphenylacetate + NADH + O2
3,4-dihydroxyphenylacetate + NAD+ + H2O
-
initial reaction in the degradation of 4-hydroxyphenylacetate
-
?
4-hydroxyphenylacetate + NADH + O2
3,4-dihydroxyphenylacetate + NAD+ + H2O
-
inducible chromosomally encoded meta-cleavage pathway of aromatic degradation
-
?
4-hydroxyphenylacetate + NADH + O2
3,4-dihydroxyphenylacetate + NAD+ + H2O
-
degradation of 4-hydroxyphenylacetate by inducible meta-cleavage pathway
-
?
4-hydroxyphenylacetate + NADH + O2
3,4-dihydroxyphenylacetate + NAD+ + H2O
-
4-hydroxyphenylacetic acid degradative pathway
-
?
4-hydroxyphenylacetate + NADH + O2
3,4-dihydroxyphenylacetate + NAD+ + H2O
-
first enzyme in 4-hydroxyphenylacetate metabolism
-
-
?
4-hydroxyphenylacetate + NADH + O2
3,4-dihydroxyphenylacetate + NAD+ + H2O
Escherichia coli B / ATCC 11303
-
enzyme is induced by 4-hydroxyphenylacetate, no constitutive synthesis
-
ir
4-hydroxyphenylacetate + NADH + O2
3,4-dihydroxyphenylacetate + NAD+ + H2O
Escherichia coli B / ATCC 11303
-
degradation of 4-hydroxyphenylacetate by inducible meta-cleavage pathway
-
?
4-hydroxyphenylacetate + NADH + O2
3,4-dihydroxyphenylacetate + NAD+ + H2O
-
enzyme is induced by 4-hydroxyphenylacetate, no constitutive synthesis
-
ir
4-hydroxyphenylacetate + NADH + O2
3,4-dihydroxyphenylacetate + NAD+ + H2O
-
degradation of 4-hydroxyphenylacetate by inducible meta-cleavage pathway
-
?
4-hydroxyphenylacetate + NADH + O2
3,4-dihydroxyphenylacetate + NAD+ + H2O
-
-
-
?
4-hydroxyphenylacetate + NADH + O2
3,4-dihydroxyphenylacetate + NAD+ + H2O
-
-
-
?
4-hydroxyphenylacetate + NADH + O2
3,4-dihydroxyphenylacetate + NAD+ + H2O
-
meta-cleavage pathway
-
?
4-hydroxyphenylacetate + NADH + O2
3,4-dihydroxyphenylacetate + NAD+ + H2O
-
-
-
?
4-hydroxyphenylacetate + NADH + O2
3,4-dihydroxyphenylacetate + NAD+ + H2O
-
-
-
?
4-hydroxyphenylacetate + NADH + O2
3,4-dihydroxyphenylacetate + NAD+ + H2O
-
-
-
?
4-hydroxyphenylacetate + NADH + O2
3,4-dihydroxyphenylacetate + NAD+ + H2O
-
-
-
?
4-hydroxyphenylacetate + NADH + O2
3,4-dihydroxyphenylacetate + NAD+ + H2O
-
-
-
?
4-hydroxyphenylacetate + NADH + O2
3,4-dihydroxyphenylacetate + NAD+ + H2O
-
-
-
?
4-hydroxyphenylacetate + NADH + O2
3,4-dihydroxyphenylacetate + NAD+ + H2O
-
enzyme is induced by 4-hydroxyphenylacetate, no constitutive synthesis
-
?
4-hydroxyphenylacetate + NADH + O2
3,4-dihydroxyphenylacetate + NAD+ + H2O
-
enzyme is induced by 4-hydroxyphenylacetate, no constitutive synthesis
-
ir
4-hydroxyphenylacetate + NADH + O2
3,4-dihydroxyphenylacetate + NAD+ + H2O
-
degradative pathway involved in the assimilation of different aromatic compounds
-
?
4-hydroxyphenylacetate + NADH + O2
3,4-dihydroxyphenylacetate + NAD+ + H2O
-
degradation of 4-hydroxyphenylacetate by inducible meta-cleavage pathway
-
?
4-hydroxyphenylacetate + NADH + O2
3,4-dihydroxyphenylacetate + NAD+ + H2O
-
degradation of 4-hydroxyphenylacetate by inducible meta-cleavage pathway
-
?
4-hydroxyphenylacetate + NADH + O2
3,4-dihydroxyphenylacetate + NAD+ + H2O
-
key enzyme in pathway of degradation of phenylalanine, tyrosine and other aromatic amines
-
?
4-hydroxyphenylacetate + NADH + O2
3,4-dihydroxyphenylacetate + NAD+ + H2O
-
enzyme is induced by 4-hydroxyphenylacetate, no constitutive synthesis
-
?
4-hydroxyphenylacetate + NADH + O2
3,4-dihydroxyphenylacetate + NAD+ + H2O
-
degradation of 4-hydroxyphenylacetate by inducible meta-cleavage pathway
-
?
3,4-dihydroxyphenylacetate + NADP+ + H2O
-
-
-
?
4-hydroxyphenylacetate + NADPH + H+ + O2
3,4-dihydroxyphenylacetate + NADP+ + H2O
Thermus thermophilus HB8 / ATCC 27634 / DSM 579
-
-
-
?
3,4-dihydroxyphenylacetic acid + H2O + NAD+
-
-
-
-
?
4-hydroxyphenylacetic acid + O2 + NADH + H+
3,4-dihydroxyphenylacetic acid + H2O + NAD+
-
-
-
-
?
4-hydroxyphenylacetic acid + O2 + NADH + H+
3,4-dihydroxyphenylacetic acid + H2O + NAD+
-
-
-
-
?
3,4-dihydroxyphenylethanol + H2O + NAD+
-
-
-
-
?
4-hydroxyphenylethanol + O2 + NADH + H+
3,4-dihydroxyphenylethanol + H2O + NAD+
-
-
-
-
?
4-hydroxyphenylethanol + O2 + NADH + H+
3,4-dihydroxyphenylethanol + H2O + NAD+
-
-
-
-
?
L-(3,4-dihydroxy)phenylalanine + FAD + H2O
-
-
-
-
?
L-tyrosine + FADH2 + O2
L-(3,4-dihydroxy)phenylalanine + FAD + H2O
-
-
-
-
?
naringin + NADH + H+ + O2
eryodictyol + NADP+ + H2O
-
-
-
?
?
-
97% of 4-hydroxyphenylacetate activity
-
-
?
?
-
-
a variety of aromatic compounds that contain a hydroxyl group in para-position can be hydroxylated. 4-hydroxyphenylacetate hydroxylase is an effector for C1 and substrate for C2
-
-
?
additional information
?
-
-
the enzyme is a two-protein system consisting of a smaller FMN reductase component C1 and a larger oxygenase component C2, C1 exists as a mixture of isoforms
-
-
?
additional information
?
-
-
the enzyme is a two-protein system consisting of a smaller FMN reductase component C1 and a larger oxygenase component C2, C1 exists as a mixture of isoforms
-
-
?
additional information
?
-
the enzyme is a two-component system consisting of a NADH-dependent FMN reductase and a monooxygenase C2, that uses reduced FMN as substrate, structure-function relationship, overview
-
-
?
additional information
?
-
-
the enzyme is a two-component system consisting of a NADH-dependent FMN reductase and a monooxygenase C2, that uses reduced FMN as substrate, structure-function relationship, overview
-
-
?
additional information
?
-
-
the enzyme is a flavin-dependent two-component monooxygenase that consists of a reductase component and an oxygenase component C2. C2 catalyzes the hydroxylation of HPA using oxygen and reduced FMN as co-substrates. All flavin-dependent monooxygenases perform oxygenation through the participation of a reactive intermediate, C4a-hydroperoxy-flavin
-
-
?
additional information
?
-
the enzyme is a flavin-dependent two-component monooxygenase that consists of a reductase component and an oxygenase component C2. C2 catalyzes the hydroxylation of HPA using oxygen and reduced FMN as co-substrates. All flavin-dependent monooxygenases perform oxygenation through the participation of a reactive intermediate, C4a-hydroperoxy-flavin
-
-
?
additional information
?
-
-
decreased accumulation of the intermediate at higher pH is due to the greater rates of C4a-hydroxy-FMN decay caused by the abolishment of substrate inhibition in the dehydration step at high pH
-
-
?
additional information
?
-
decreased accumulation of the intermediate at higher pH is due to the greater rates of C4a-hydroxy-FMN decay caused by the abolishment of substrate inhibition in the dehydration step at high pH
-
-
?
additional information
?
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in the absence of 4-hydroxyphenylacetate, the rate constant for the formation of C4a-hydroperoxy-FMN is unaffected at pH 6.2-9.9. The rate constant for the following H2O2 elimination step increases with higher pH, consistent with a pKa above 9.4. In the presence of 4-hydroxyphenylacetate, the rate constants for the formation of C4a-hydroperoxy-FMN and the ensuing hydroxylation step are not significantly affected by the pH. In contrast, the following steps of C4a-hydroxy-FMN dehydration to form oxidized FMN occur through two pathways that are dependent on the pH of the reaction. One pathway, dominant at low pH, allows the detection of a C4a-hydroxy-FMN intermediate, whereas the pathway dominant at high pH produces oxidized FMN without an apparent accumulation of the intermediate. Both pathways efficiently catalyze hydroxylation without generating significant amounts of wasteful H2O2 at pH 6.2-9.9
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in the absence of 4-hydroxyphenylacetate, the rate constant for the formation of C4a-hydroperoxy-FMN is unaffected at pH 6.2-9.9. The rate constant for the following H2O2 elimination step increases with higher pH, consistent with a pKa above 9.4. In the presence of 4-hydroxyphenylacetate, the rate constants for the formation of C4a-hydroperoxy-FMN and the ensuing hydroxylation step are not significantly affected by the pH. In contrast, the following steps of C4a-hydroxy-FMN dehydration to form oxidized FMN occur through two pathways that are dependent on the pH of the reaction. One pathway, dominant at low pH, allows the detection of a C4a-hydroxy-FMN intermediate, whereas the pathway dominant at high pH produces oxidized FMN without an apparent accumulation of the intermediate. Both pathways efficiently catalyze hydroxylation without generating significant amounts of wasteful H2O2 at pH 6.2-9.9
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the enzyme utilizes the C-terminal domain of the reductase component as an autoinhibitory domain to suppress both the rate of reduction of FMN and the rate of release of FMNH2 from the reductase component
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proton transfer is not the rate-limiting step in the formation of the C4a-(hydro)peroxyflavin intermediate. Residue His396 may act as an instantaneous proton provider for the proton-coupled electron transfer that occurs before the transition state of C4a-(hydro)peroxyflavin formation
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the protonation of dioxygen by residue His396 of hte oxygenase component via a proton-coupled electron transfer mechanism is the key step in the formation of the triplet diradical complex of flavin semiquinone and the hydroperoxide radical. The complex undergoes intersystem crossing to form the open-shell singlet diradical complex before it forms the closed-shell singlet C4a-hydroperoxyflavin intermediate. The formation of C4a-hydroperoxyflavin is nearly barrierless. The enthalpy of activation for the formation of C4a-hydroperoxyflavin is only 1.4 kcal/mol and the formation is fast. Ser171 is the key residue that stabilizes C4a-hydroperoxyflavin by accepting a hydrogen bond from the H(N5) of the isoalloxazine ring. Both Ser171 and Trp112 facilitate H2O2 elimination by donating hydrogen bonds to the proximal oxygen of the hydroperoxide moiety during the proton transfer
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wild-type shows a hydroxylation rate constant (kOH) for 4-aminophenylacetate of 0.028 per s compared to 17 per s for 4-hydroxyphenylacetate. Mutant S146A shows hydroxylation rate constants of 2.6 per s for 4-aminophenylacetate compared to 2.5 per s for 4-hydroxyphenylacetate
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wild-type shows a hydroxylation rate constant (kOH) for 4-aminophenylacetate of 0.028 per s compared to 17 per s for 4-hydroxyphenylacetate. Mutant S146A shows hydroxylation rate constants of 2.6 per s for 4-aminophenylacetate compared to 2.5 per s for 4-hydroxyphenylacetate
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rather broad substrate specificity, acting on mono- and dihydric phenols. Several substrates are below 50% of activity
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3- and 4-hydroxyphenylacetate are both catalyzed by 3- or 4-hydroxyphenylacetate hydroxylase by the same route with 3,4-dihydroxyphenylacetate as the first common intermediate, cells grown on one compound are fully induced for the catabolism of the other
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the enzyme does not form stable complexes or channel substrates with the NAD(P)H-flavin oxidoredctase HpaC, but NAD(P)H-flavin oxidoreductase HpaC is required for delivering of sufficient amounts of FADH2
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no substrates: benzoic acid, dihydroxybenzoic acid, 4-methoxyphenylacetic acid, catechol, 4-hydroxy-D-2-phenylglycine, 4-hydroxy-L-2-phenylglycine, 3-hydroxy-4-methoxyphenylacetic acid, 4-tert-butylphenol, 3-methoxyphenylacetic acid, 4-hydroxy-3-methoxyphenylacetic acid
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Escherichia coli B / ATCC 11303
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3- and 4-hydroxyphenylacetate are both catalyzed by 3- or 4-hydroxyphenylacetate hydroxylase by the same route with 3,4-dihydroxyphenylacetate as the first common intermediate, cells grown on one compound are fully induced for the catabolism of the other
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3- and 4-hydroxyphenylacetate are both catalyzed by 3- or 4-hydroxyphenylacetate hydroxylase by the same route with 3,4-dihydroxyphenylacetate as the first common intermediate, cells grown on one compound are fully induced for the catabolism of the other
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dihydroxylated compounds are transformed, no reaction with phenylacetate, 4-chlorobenzoate or 2-hydroxyphenylacetate
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no or very low oxidation activity toward cinnamic acid, o-coumaric acid and m-coumaric acid
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no or very low oxidation activity toward cinnamic acid, o-coumaric acid and m-coumaric acid
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broad substrate range. Several other substrates show activities below 50%. The length of the acetyl moiety is very important in substrate recognition
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substrates become hydroxylated at a position ortho to the hydroxyl group, 4-chlorophenylacetate, 4-fluorobenzoate and benzoate are not hydroxylated
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the oxygenase HpaB is a component of the 4-hydroxyphenylacetate 3-monooxygenase enzyme that is responsible for the hydroxylation of 4-hydroxyphenylacetate. It utilizes molecular oxygen and a reduced flavin, which is provided by HpaC, the second component of the enzyme
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the oxygenase HpaB is a component of the 4-hydroxyphenylacetate 3-monooxygenase enzyme that is responsible for the hydroxylation of 4-hydroxyphenylacetate. It utilizes molecular oxygen and a reduced flavin, which is provided by HpaC, the second component of the enzyme
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the hydroxylation of 4-hydroxyphenylacetate by this oxygenase is performed in two stages. Firstly, the reductase component of the enzyme, the small 16.1 kDa protein HpaC, reduces flavin with the use of NAD(P)H. Subsequently, reduced flavin is transported to the oxygenase component HpaB of 4HPA 3-monooxygenase by free diffusion where, together with the oxygen molecule, it is used for the oxygenation of substrates. HpaB determines the substrate specificity
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additional information
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the hydroxylation of 4-hydroxyphenylacetate by this oxygenase is performed in two stages. Firstly, the reductase component of the enzyme, the small 16.1 kDa protein HpaC, reduces flavin with the use of NAD(P)H. Subsequently, reduced flavin is transported to the oxygenase component HpaB of 4HPA 3-monooxygenase by free diffusion where, together with the oxygen molecule, it is used for the oxygenation of substrates. HpaB determines the substrate specificity
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Thermus thermophilus HB8 / ATCC 27634 / DSM 579
the oxygenase HpaB is a component of the 4-hydroxyphenylacetate 3-monooxygenase enzyme that is responsible for the hydroxylation of 4-hydroxyphenylacetate. It utilizes molecular oxygen and a reduced flavin, which is provided by HpaC, the second component of the enzyme
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Thermus thermophilus HB8 / ATCC 27634 / DSM 579
the hydroxylation of 4-hydroxyphenylacetate by this oxygenase is performed in two stages. Firstly, the reductase component of the enzyme, the small 16.1 kDa protein HpaC, reduces flavin with the use of NAD(P)H. Subsequently, reduced flavin is transported to the oxygenase component HpaB of 4HPA 3-monooxygenase by free diffusion where, together with the oxygen molecule, it is used for the oxygenation of substrates. HpaB determines the substrate specificity
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