Any feedback?
Information on EC 1.7.1.B3 - aromatic nitroreductase [NADPH]
for references in articles please use BRENDA:EC1.7.1.B3preliminary BRENDA-supplied EC number
Please wait a moment until all data is loaded. This message will disappear when all data is loaded.
EC Tree
1.7.1.B3 aromatic nitroreductase [NADPH]Specify your search results
Word Map
- 1.7.1.B3
-
hypoplasia
-
dermal
-
x-linked
-
goltz
-
ectodermal
-
malformation
-
ocular
-
porcupine
-
mesoderm
-
blaschko
-
skew
-
x-chromosome
-
postzygotic
-
teeth
-
goltz-gorlin
-
multisystemic
-
herniation
-
diaphragmatic
-
x-inactivation
-
angioma
-
papillomas
-
hernia
-
wingless
-
cutis
-
nail
-
o-acyltransferase
-
aplasia
-
patchy
- environmental protection
- medicine
The expected taxonomic range for this enzyme is: Bacteria, Eukaryota
Reaction Schemes
+
3
+
2
=
+
3
+
3
Synonyms
nitrofurazone reductase, oxygen-insensitive nad(p)h:nitroreductases, 
more
topPlease wait a moment until the data is sorted. This message will disappear when the data is sorted.
SYNONYM 
ORGANISM
UNIPROT
COMMENTARY 
LITERATURE
NfsA
nitroreductase A
ORF 17150
oxygen-insensitive nitroreductase (NADPH)
-
-
-
-
additional information
NfsA
-
-
ambiguous
-
Please wait a moment until the data is sorted. This message will disappear when the data is sorted.
REACTION
REACTION DIAGRAM
COMMENTARY
ORGANISM
UNIPROT
LITERATURE
an aromatic amine + NADP+ + H2O = an aromatic hydroxylamine + NADPH + H+
(1a)
-
-
-
an aromatic hydroxylamine + NADP+ = an aromatic nitric oxide + NADPH + H+
(1b)
-
-
-
an aromatic nitric oxide + NADP+ + H2O = an aromatic nitrate + NADPH + H+
(1c)
-
-
-
an aromatic amine + 3 NADP+ + 2 H2O = an aromatic nitrate + 3 NADPH + 3 H+
(overall reaction)
-
-
-
an aromatic amine + 3 NADP+ + 2 H2O = an aromatic nitrate + 3 NADPH + 3 H+
in vivo the reaction is obseverved in the opposite direction from that shown in the equation
-
-
-
an aromatic amine + 3 NADP+ + 2 H2O = an aromatic nitrate + 3 NADPH + 3 H+
catalytic mechanism analysis, two (four)-electron reduction of nitrobenzenes and single-step (H-) hydride transfer mechanism. NfsA follows a ping-pong mechanism, overview
-
an aromatic amine + 3 NADP+ + 2 H2O = an aromatic nitrate + 3 NADPH + 3 H+
the enzyme catalysis obeys the ping-pong Bi-Bi kinetic mechanism with substrate FMN as well as substrate nitrofurazone, but upon coupling with the bioluminescent reaction of luciferase, it changes to the sequential mechanism
-
an aromatic amine + 3 NADP+ + 2 H2O = an aromatic nitrate + 3 NADPH + 3 H+
the enzyme uses NADPH as the hydrogen donor to catalyze the reduction of a nitro group by a ping-pong Bi-Bi kinetic mechanism
an aromatic amine + 3 NADP+ + 2 H2O = an aromatic nitrate + 3 NADPH + 3 H+
the enzyme catalysis obeys the ping-pong Bi-Bi kinetic mechanism with substrate FMN as well as substrate nitrofurazone, but upon coupling with the bioluminescent reaction of luciferase, it changes to the sequential mechanism
-
-
Please wait a moment until the data is sorted. This message will disappear when the data is sorted.
SYSTEMATIC NAME
IUBMB Comments
aromatic nitrate:NADPH oxidroreductase
-
Please wait a moment until the data is sorted. This message will disappear when the data is sorted.
SUBSTRATE
PRODUCT
REACTION DIAGRAM
ORGANISM
UNIPROT
COMMENTARY
(Substrate)
(Substrate)
LITERATURE
(Substrate)
(Substrate)
COMMENTARY
(Product)
(Product)
LITERATURE
(Product)
(Product)
Reversibility
r=reversible
ir=irreversible
?=not specified
r=reversible
ir=irreversible
?=not specified
nitro-CBI-5-[(dimethylamino)ethoxy]indole + NAD(P)H + H+
? + NAD(P)+
a nitro-CBI prodrug, low activity
-
-
?
nitrofurazone + NADPH + H+
5-(hydroxyamino)furan-2-carbaldehyde semicarbazone + NADP+ + H2O
2,4,6-trinitrotoluene + NADPH + H+
4-hydroxylamino-2,6-dinitrotoluene + NADP+ + H2O
-
-
-
?
2,4,6-trinitrotoluene + NADPH + H+
4-hydroxylamino-2,6-dinitrotoluene + NADP+ + H2O
i.e. TNT, NfsA reduces TNT to the para isomer 4-hydroxylamino-2,6-dinitrotoluene more easily than the ortho isomer 2-hydroxylamino-4,6-dinitrotoluene
-
-
?
5-(aziridin-1-yl)-2,4-dinitrobenzamide + NADPH + H+
? + NADP+
-
i.e. CB1954, an aziridinyl dinitrobenzamide prodrug
-
-
?
5-(aziridin-1-yl)-2,4-dinitrobenzamide + NADPH + H+
? + NADP+
i.e. CB1954, an aziridinyl dinitrobenzamide prodrug
-
-
?
7-nitrocoumarin + 3 NADPH + 3 H+
7-aminocoumarin + 3 NADP+
-
-
-
?
7-nitrocoumarin + 3 NADPH + 3 H+
7-aminocoumarin + 3 NADP+
-
-
-
-
?
nitrofurazone + NADPH + H+
5-(hydroxyamino)furan-2-carbaldehyde semicarbazone + NADP+ + H2O
-
-
-
-
?
nitrofurazone + NADPH + H+
5-(hydroxyamino)furan-2-carbaldehyde semicarbazone + NADP+ + H2O
-
-
-
?
additional information
?
-
-
the enzyme reduces both nitrofurazone and FMN effectively, see for EC 1.5.1.38, it is bifunctional as flavin reductase and nitroreductase. Two different FMN molecules are involved in the FMN reduction process: FMN tightly associated to the enzyme as prosthetic group and FMN as a substrate. The enzyme is also active with FAD, riboflavin, and lumiflavin, the two latter give the highest activity
-
-
?
additional information
?
-
an intrinsically oxygen-insensitive nature of the two-electron reduction mechanism
-
-
?
additional information
?
-
-
NADPH-dependent reduction of quinones, cf. EC 1.6.5.5, and nitroaromatic compounds by NfsA, overview. The reactivity of nitroaromatic compounds (log kcat/Km) follows a linear dependence on their single-electron reduction potential, indicating a limited role for compound structure or active site flexibility in their reactivity. The reactivity of quinones is lower than that of nitroaromatics having similar single-electron reduction potential values, except for the significantly enhanced reactivity of 2-OH-1,4-naphthoquinones. The reduction of quinones by NfsA is most consistent with a single-step (H-) hydride transfer mechanism, quantitative analysis of two-electron reduction of quinones and nitroaromatics, overview
-
-
?
additional information
?
-
NfsA has a broad substrate spectrum. Various nitroaromatic substrates, including 5-(aziridin-1-yl)-2,4-dinitrobenzamide (CB1954), 2,4,6-trinitrotoluene (TNT), and 2,4-dinitrotoluene (2,4-DNT), can serve as substrates
-
-
?
additional information
?
-
no activity with 2,4-diamino-6-nitrotoluene and 2,6-diamino-4-nitrotoluene
-
-
?
additional information
?
-
coenzyme Q and tetracycline may be used as electron acceptors, but with much lower specific activities than menadione, cf EC 1.6.5.5. Nitro compounds dinitrotoluene, 7-nitrocoumarin, and metronidazole can be used as electron acceptors
-
-
-
additional information
?
-
-
coenzyme Q and tetracycline may be used as electron acceptors, but with much lower specific activities than menadione, cf EC 1.6.5.5. Nitro compounds dinitrotoluene, 7-nitrocoumarin, and metronidazole can be used as electron acceptors
-
-
-
Please wait a moment until the data is sorted. This message will disappear when the data is sorted.
NATURAL SUBSTRATE
NATURAL PRODUCT
REACTION DIAGRAM
ORGANISM
UNIPROT
COMMENTARY
(Substrate)
(Substrate)
LITERATURE
(Substrate)
(Substrate)
COMMENTARY
(Product)
(Product)
LITERATURE
(Product)
(Product)
REVERSIBILITY
r=reversible
ir=irreversible
?=not specified
r=reversible
ir=irreversible
?=not specified
2,4,6-trinitrotoluene + NADPH + H+
4-hydroxylamino-2,6-dinitrotoluene + NADP+ + H2O
-
-
-
?
nitrofurazone + NADPH + H+
5-(hydroxyamino)furan-2-carbaldehyde semicarbazone + NADP+ + H2O
-
-
-
-
?
Please wait a moment until the data is sorted. This message will disappear when the data is sorted.
COFACTOR
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
IMAGE
FMN
-
tightly associated to, two different FMN molecules are involved in the FMN reduction process: FMN tightly associated to the enzyme as prosthetic group and FMN as a substrate
Please wait a moment until the data is sorted. This message will disappear when the data is sorted.
INHIBITOR
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
IMAGE
dicoumarol
-
inhibits Escherichia coli enzyme NfsB far more strongly than enzyme NfsA, by acting as a competitive inhibitor towards NADPH, uncompetitive towards substrate tetryl
Please wait a moment until the data is sorted. This message will disappear when the data is sorted.
KM VALUE [mM]
SUBSTRATE
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
IMAGE
0.3257
2-amino-4,6-dinitrotoluene
pH 7.0, 37°C, recombinant His6-tagged enzyme
0.6427
4-amino-2,6-dinitrotoluene
pH 7.0, 37°C, recombinant His6-tagged enzyme
0.029
2,4,6-trinitrotoluene
recombinant wild-type enzyme, pH 7.0, 22°C
0.029
2,4,6-trinitrotoluene
pH 7.0, 37°C, recombinant His6-tagged enzyme
0.322
5-(aziridin-1-yl)-2,4-dinitrobenzamide
recombinant mutant F46Y, pH 7.0, 22°C
0.327
5-(aziridin-1-yl)-2,4-dinitrobenzamide
recombinant wild-type enzyme, pH 7.0, 22°C
0.332
5-(aziridin-1-yl)-2,4-dinitrobenzamide
recombinant mutant F46Y, pH 7.0, 22°C
0.487
5-(aziridin-1-yl)-2,4-dinitrobenzamide
recombinant mutant F46Y, pH 7.0, 22°C
additional information
additional information
Michaelis-Menten steady-state kinetics
-
additional information
additional information
-
enzyme kinetic analysis, overview
-
additional information
additional information
Michaelis-Menten steady-state kinetics of recombinant His6-tagged enzyme
-
additional information
additional information
-
Michaelis-Menten steady-state kinetics. For NfsA the oxidative half-reaction (i.e., the reoxidation of FMNH by the oxidant substrate) is a rate-limiting step, because the values of kcat at infinite concentrations of tetryl or 2,4,6-trinitrotoluene are substantially lower than the lowest rate of the reductive half reaction (the reduction of FMN by NADPH) measured in the preliminary rapid reaction experiments. Stopped-flow and single-turnover measurements
-
Please wait a moment until the data is sorted. This message will disappear when the data is sorted.
TURNOVER NUMBER [1/s]
SUBSTRATE
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
IMAGE
12.36
2-amino-4,6-dinitrotoluene
pH 7.0, 37°C, recombinant His6-tagged enzyme
1.05
4-amino-2,6-dinitrotoluene
pH 7.0, 37°C, recombinant His6-tagged enzyme
56.2
2,4,6-trinitrotoluene
pH 7.0, 37°C, recombinant His6-tagged enzyme
56.21
2,4,6-trinitrotoluene
recombinant wild-type enzyme, pH 7.0, 22°C
1.08
5-(aziridin-1-yl)-2,4-dinitrobenzamide
recombinant mutant F46Y, pH 7.0, 22°C
2.99
5-(aziridin-1-yl)-2,4-dinitrobenzamide
recombinant mutant F46Y, pH 7.0, 22°C
24.27
5-(aziridin-1-yl)-2,4-dinitrobenzamide
recombinant mutant F46Y, pH 7.0, 22°C
36.64
5-(aziridin-1-yl)-2,4-dinitrobenzamide
recombinant wild-type enzyme, pH 7.0, 22°C
Please wait a moment until the data is sorted. This message will disappear when the data is sorted.
kcat/KM VALUE [1/mMs-1]
SUBSTRATE
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
IMAGE
38
2-amino-4,6-dinitrotoluene
pH 7.0, 37°C, recombinant His6-tagged enzyme
1.6
4-amino-2,6-dinitrotoluene
pH 7.0, 37°C, recombinant His6-tagged enzyme
1931
2,4,6-trinitrotoluene
pH 7.0, 37°C, recombinant His6-tagged enzyme
1940
2,4,6-trinitrotoluene
recombinant wild-type enzyme, pH 7.0, 22°C
2
5-(aziridin-1-yl)-2,4-dinitrobenzamide
recombinant mutant F46Y, pH 7.0, 22°C
9
5-(aziridin-1-yl)-2,4-dinitrobenzamide
recombinant mutant F46Y, pH 7.0, 22°C
75
5-(aziridin-1-yl)-2,4-dinitrobenzamide
recombinant mutant F46Y, pH 7.0, 22°C
112
5-(aziridin-1-yl)-2,4-dinitrobenzamide
recombinant wild-type enzyme, pH 7.0, 22°C
Please wait a moment until the data is sorted. This message will disappear when the data is sorted.
Ki VALUE [mM]
INHIBITOR
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
IMAGE
Please wait a moment until the data is sorted. This message will disappear when the data is sorted.
SPECIFIC ACTIVITY [µmol/min/mg]
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
0.1
purified recombinant mutant F46A, pH 7.0, 22°C, substrate nitrofurazone
0.29
purified recombinant mutant F46N, pH 7.0, 22°C, substrate nitrofurazone
3.74
purified recombinant mutant F46Y, pH 7.0, 22°C, substrate nitrofurazone
7.75
purified recombinant wild-type enzyme, pH 7.0, 22°C, substrate nitrofurazone
Please wait a moment until the data is sorted. This message will disappear when the data is sorted.
pH OPTIMUM
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
Please wait a moment until the data is sorted. This message will disappear when the data is sorted.
TEMPERATURE OPTIMUM
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
Please wait a moment until the data is sorted. This message will disappear when the data is sorted.
ORGANISM
COMMENTARY
LITERATURE
UNIPROT
SEQUENCE DB
SOURCE
Please wait a moment until the data is sorted. This message will disappear when the data is sorted.
GENERAL INFORMATION
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
evolution
physiological function
additional information
evolution
-
analysis of evolutionary or molecular mechanism of divergence of the nitroreductase/flavin reductase family, overview. The enzyme is similar to NfsA from Escherichia coli, overview
evolution
nitroreductases are a family of flavoproteins that catalyze the NAD(P)H-dependent reduction of nitro groups to hydroxylamino and/or amino groups on various nitro-substituted compounds
evolution
-
analysis of evolutionary or molecular mechanism of divergence of the nitroreductase/flavin reductase family, overview. The enzyme is similar to NfsA from Escherichia coli, overview
-
physiological function
-
NfsA has potential applications in the biodegradation of nitroaromatic environment pollutants, e.g. explosives, and is also of interest for the anticancer strategy gene-directed enzyme prodrug therapy
physiological function
residue Phe42 is critical for the catalytic activity of Escherichia coli major nitroreductase NfsA, Phe42 is important for maintaining NfsA activity and structure
physiological function
enzyme is a flavoprotein with NADPH-dependent quinone reductase and nitroreductase activities
physiological function
-
enzyme is a flavoprotein with NADPH-dependent quinone reductase and nitroreductase activities
-
additional information
-
comparisons of the quantitative structure-activity relationships of single-electron reduction of quinones and nitroaromatic compounds by dehydrogenase (electron transferase) flavoenzymes, overview
additional information
the enzyme crystal structure of NfsA, PDB ID 1F5V, is used for molecular ligand docking studies
Please wait a moment until the data is sorted. This message will disappear when the data is sorted.
UNIPROT
ENTRY NAME
ORGANISM
NO. OF AA
NO. OF TRANSM. HELICES
MOLECULAR WEIGHT[Da]
SOURCE
SEQUENCE
LOCALIZATION PREDICTION
The reliability class of the localization prediction ranges from 1 (very reliable) to 5 (not reliable).
The reliability class of the localization prediction ranges from 1 (very reliable) to 5 (not reliable). A8BSH8_GIAIC
Giardia intestinalis (strain ATCC 50803 / WB clone C6)
164
0
18583
TrEMBL
-