Information on EC 1.6.2.2 - cytochrome-b5 reductase

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The enzyme appears in viruses and cellular organisms

EC NUMBER
COMMENTARY hide
1.6.2.2
-
RECOMMENDED NAME
GeneOntology No.
cytochrome-b5 reductase
REACTION
REACTION DIAGRAM
COMMENTARY hide
ORGANISM
UNIPROT
LITERATURE
NADH + 2 ferricytochrome b5 = NAD+ + H+ + 2 ferrocytochrome b5
show the reaction diagram
REACTION TYPE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
oxidation
-
-
-
-
redox reaction
-
-
-
-
reduction
-
-
-
-
PATHWAY
BRENDA Link
KEGG Link
MetaCyc Link
Amino sugar and nucleotide sugar metabolism
-
-
SYSTEMATIC NAME
IUBMB Comments
NADH:ferricytochrome-b5 oxidoreductase
A flavoprotein (FAD).
CAS REGISTRY NUMBER
COMMENTARY hide
9032-25-1
-
ORGANISM
COMMENTARY hide
LITERATURE
UNIPROT
SEQUENCE DB
SOURCE
turnip
-
-
Manually annotated by BRENDA team
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-
-
Manually annotated by BRENDA team
-
-
-
Manually annotated by BRENDA team
L. cv. Ogosta
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-
Manually annotated by BRENDA team
learn-pyrethroid-resistance strain, house fly
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-
Manually annotated by BRENDA team
akkaraman sheep
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-
Manually annotated by BRENDA team
L. cv Dobrujanski 7
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Manually annotated by BRENDA team
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-
-
Manually annotated by BRENDA team
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-
-
Manually annotated by BRENDA team
potato
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-
Manually annotated by BRENDA team
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UniProt
Manually annotated by BRENDA team
GENERAL INFORMATION
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
evolution
-
CyB5R is a member of the NAD(P)H-ferredoxin reductase (FNR) enzyme superfamily, phylogenetic analysis
malfunction
metabolism
physiological function
additional information
SUBSTRATE
PRODUCT                       
REACTION DIAGRAM
ORGANISM
UNIPROT
COMMENTARY
(Substrate) hide
LITERATURE
(Substrate)
COMMENTARY
(Product) hide
LITERATURE
(Product)
Reversibility
r=reversible
ir=irreversible
?=not specified
1,2-dihydro-8-(4-methylpiperazin-1-yl)-4-phenylimidazol[3,2-e]pyrazine 5-oxide + NADH
1,2-dihydro-8-(4-methylpiperazin-1-yl)-4-phenylimidazol[3,2-e]pyrazine + NAD+
show the reaction diagram
-
potential bioreductive drug, trivial name RB90740
-
?
2 ferricyanide + NADH
2 ferrocyanide + NAD+ + H+
show the reaction diagram
2 ferricyanide + NADPH
2 ferrocyanide + NADP+ + H+
show the reaction diagram
2 ferricytochrome b5 + NADH
2 ferrocytochrome b5 + NAD+ + H+
show the reaction diagram
2 ferricytochrome b5 + NADPH
2 ferrocytochrome b5 + NADP+ + H+
show the reaction diagram
with NADPH the enzyme shows about 20% of the activity with NADH
-
-
?
2 ferricytochrome c + NADH
2 ferrocytochrome c + NAD+ + H+
show the reaction diagram
2-[4-iodophenyl]-3-[4-nitrophenyl]-5-[2,4-disulfophenyl]-2H tetrazolium monosodium salt + NADH
?
show the reaction diagram
-
-
-
?
5alpha-dihydrotestosterone + acceptor
?
show the reaction diagram
-
-
-
-
r
aquacobalamin + NADH
reduced aquacobalamin + NAD+
show the reaction diagram
-
in the presence of outer membrane cytochrome b, no activity with cyanocobalamin
-
?
benzamidoxime + NADH
?
show the reaction diagram
-
in the presence of cytochrome b5
-
-
?
Cu2+-citrate + NADH
Cu+-citrate + NAD+
show the reaction diagram
dapsone hydroxylamine + NADH
?
show the reaction diagram
-
in the presence of cytochrome b5
-
-
?
deoxyhemerythrin + O2
?
show the reaction diagram
-
-
-
-
?
Fe3+-ammonium sulfate + NADH
Fe2+-ammonium sulfate + NAD+
show the reaction diagram
-
strongly elevated by the addition of cytochrome b5
-
?
Fe3+-ATP + NADH
Fe2+-ATP + NAD+
show the reaction diagram
Fe3+-citrate + NADH
Fe2+-citrate + NAD+
show the reaction diagram
Fe3+-EDTA + NADH
Fe2+-EDTA + NAD+
show the reaction diagram
Fe3+-histidine + NADH
Fe2+-histidine + NAD+
show the reaction diagram
-
strongly elevated by the addition of cytochrome b5
-
?
Fe3+-nitrilotriacetate + NADH
Fe2+-nitrilotriacetate + NAD+
show the reaction diagram
-
in the presence of cytochrome b5, iron chelate reduction in descending order: Fe3+-nitrolotriacetate, Fe3+-ADP, Fe3+-diphosphate, Fe3+-citrate
-
?
ferricytochrome b5 + 4-(5-(4-[amino(hydroxyamino)methyl]phenyl)-2-furyl)-N'-hydroxybenzenecarboximidamide
ferrocytochrome b5 + ?
show the reaction diagram
-
metabolite of DB289, an antimicrobial prodrug of furamidine
-
-
?
ferricytochrome b5 + 4-(5-(4-[amino(hydroxyamino)methyl]phenyl)-2-furyl)-N'-methoxybenzenecarboximidamide
ferrocytochrome b5 + ?
show the reaction diagram
-
metabolite of DB289, an antimicrobial prodrug of furamidine
-
-
?
ferricytochrome b5 + N-hydroxy-2-amino-1-methyl-6-phenylimidazol[4,5-b]pyridine
ferrocytochrome b5 + ?
show the reaction diagram
-
arylhydroxylamine carcinogen found in grilled meat
-
-
?
ferricytochrome b5 + N-hydroxy-4-aminobiphenyl
ferrocytochrome b5 + ?
show the reaction diagram
-
arylhydroxylamine carcinogen found in cigarette smoke
-
-
?
lucigenin + NADH
?
show the reaction diagram
-
-
-
?
methemerythrin + NADH
deoxymethemerythrin + NAD+
show the reaction diagram
methemoglobin + NADH
hemoglobin + NAD+
show the reaction diagram
-
provides functional hemoglobin
-
-
?
methemoglobin-ferrocyanide complex + NADH
reduced methemoglobin-ferrocyanide complex + NAD+
show the reaction diagram
-
-
-
?
NADH + ferricyanide
NAD+ + H+ + ferrocyanide
show the reaction diagram
NADH + ferricytochrome b5
NAD+ + H+ + ferrocytochrome b5
show the reaction diagram
NADH + ferricytochrome b5 + oxidized soluble guanylate cyclase
NAD+ + H+ + ferrocytochrome b5 + reduced soluble guanylate cyclase
show the reaction diagram
-
-
-
-
?
NADH + ferricytochrome c
NAD+ + H+ + ferrocytochrome c
show the reaction diagram
-
-
-
-
?
NADH + methemoglobin
NAD+ + hemoglobin
show the reaction diagram
-
-
-
-
?
NADH + oxidized 2,6-dichlorophenolindophenol
NAD+ + H+ + reduced 2,6-dichlorophenolindophenol
show the reaction diagram
NADH + oxidized cytochrome c
NAD+ + H+ + reduced cytochrome c
show the reaction diagram
-
-
-
-
?
NADH + oxidized nitroblue tetrazolium
NAD+ + H+ + reduced nitroblue tetrazolium
show the reaction diagram
-
-
-
-
?
NADPH + ferricytochrome b5
NADP+ + H+ + ferrocytochrome b5
show the reaction diagram
-
low affinity for NADPH
-
-
?
sulfamethoxazole hydroxylamine + NADH
?
show the reaction diagram
-
in the presence of cytochrome b5
-
-
?
additional information
?
-
NATURAL SUBSTRATES
NATURAL PRODUCTS
REACTION DIAGRAM
ORGANISM
UNIPROT
COMMENTARY
(Substrate) hide
LITERATURE
(Substrate)
COMMENTARY
(Product) hide
LITERATURE
(Product)
REVERSIBILITY
r=reversible
ir=irreversible
?=not specified
2 ferricytochrome b5 + NADH
2 ferrocytochrome b5 + NAD+ + H+
show the reaction diagram
5alpha-dihydrotestosterone + acceptor
?
show the reaction diagram
-
-
-
-
r
benzamidoxime + NADH
?
show the reaction diagram
-
in the presence of cytochrome b5
-
-
?
dapsone hydroxylamine + NADH
?
show the reaction diagram
-
in the presence of cytochrome b5
-
-
?
deoxyhemerythrin + O2
?
show the reaction diagram
-
-
-
-
?
methemoglobin + NADH
hemoglobin + NAD+
show the reaction diagram
-
provides functional hemoglobin
-
-
?
NADH + ferricytochrome b5
NAD+ + H+ + ferrocytochrome b5
show the reaction diagram
NADH + ferricytochrome b5 + oxidized soluble guanylate cyclase
NAD+ + H+ + ferrocytochrome b5 + reduced soluble guanylate cyclase
show the reaction diagram
-
-
-
-
?
NADH + methemoglobin
NAD+ + hemoglobin
show the reaction diagram
-
-
-
-
?
sulfamethoxazole hydroxylamine + NADH
?
show the reaction diagram
-
in the presence of cytochrome b5
-
-
?
additional information
?
-
COFACTOR
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
NADPH
METALS and IONS
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
Mg2+
-
half maximal activation at 1 mM
additional information
INHIBITORS
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
(+)-catechin
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(+)-taxifolin
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(-)-epicatechin
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(5Z)-5-[(9H-fluoren-3-yl)methylidene]-1-(4-methylphenyl)-2-sulfanylidenedihydropyrimidine-4,6(1H,5H)-dione
-
about 80% inhibition at 0.5 mM
(5Z)-5-{[4-bromo-5-(morpholin-4-yl)furan-2-yl]methylidene}-1-(4-methylphenyl)-2-sulfanylidenedihydropyrimidine-4,6(1H,5H)-dione
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about 5% inhibition at 0.5 mM
1,10-phenanthroline
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1-(2-fluorophenyl)-5-[(1-methyl-2,3-dihydro-1H-indol-3-yl)methyl]-2-sulfanylidenedihydropyrimidine-4,6(1H,5H)-dione
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about 75% inhibition at 0.5 mM
2,2'-dipyridyl
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-
2-methyl-6-[(phenylsulfanyl)methyl]-2,5-dihydropyrimidin-4(3H)-one
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about 5% inhibition at 0.5 mM
4-({[(2S)-2,3-dihydro-1,3-benzoxazol-2-yl]sulfanyl}methyl)tetrahydropyrimidine-2,5-dione
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about 45% inhibition at 0.5 mM
5'-(p-fluorosulfonylbenzoyl)-adenosine
-
-
5-(prop-2-en-1-yl)-6-propyl-2-sulfanylidene-2,3-dihydropyrimidin-4(1H)-one
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about 75% inhibition at 0.5 mM
5-propyl-2-thiouracil
-
25 mM, almost complete inhibition
6-(pentyloxy)-2-sulfanylidene-2,3-dihydropyrimidin-4(1H)-one
-
about 25% inhibition at 0.05 mM
6-([[(2R)-2,3-dihydro-1,3-benzoxazol-2-yl]sulfanyl]methyl)-2-sulfanylidene-2,3-dihydropyrimidin-4(1H)-one
-
complete inhibition at 0.05 mM
6-benzyl-2-sulfanylidene-2,3-dihydropyrimidin-4(1H)-one
-
about 3% inhibition at 0.5 mM
6-pentyl-2-sulfanylidene-2,3-dihydropyrimidin-4(1H)-one
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about 25% inhibition at 0.5 mM
6-Propyl-2-thiouracil
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about 20% residual activity at 0.009 mM
6-[(phenylsulfanyl)methyl]-2-sulfanylidene-2,3-dihydropyrimidin-4(1H)-one
-
complete inhibition at 0.05 mM
6-[(phenylsulfanyl)methyl]pyrimidine-2,4(1H,3H)-dione
-
about 50% inhibition at 0.5 mM
6-{[(2,6-dichlorophenyl)sulfanyl]methyl}-2-sulfanylidene-2,3-dihydropyrimidin-4(1H)-one
-
complete inhibition at 0.05 mM
6-{[(4-bromophenyl)sulfanyl]methyl}-2-sulfanylidene-2,3-dihydropyrimidin-4(1H)-one
-
about 10% inhibition at 0.05 mM
6-{[(4-methylphenyl)sulfanyl]methyl}-2-sulfanylidene-2,3-dihydropyrimidin-4(1H)-one
-
about 85% inhibition at 0.05 mM
6-{[(propan-2-yl)sulfanyl]methyl}-2-sulfanylidene-2,3-dihydropyrimidin-4(1H)-one
-
about 18% inhibition at 0.05 mM
acetate
-
-
Acrynol
adenine nucleotides
apigenin
-
-
apocynin
-
90.1% inhibition at 0.2 mM
Atebrin
Benzoate
-
complete inhibition at 1 mM
benzyl alcohol
-
100 mM, 52% inhibition, reversible, may be due to changes in membrane fluidity
Br-
-
competitive vs. cytochrome b5, reversible by dilution
Ca2+
-
23.5% residual activity at 1 mM
CaCl2
-
8 mM, 50% inhibition, competitive vs. cytochrome b5
citrate
-
-
dicoumarol
dithiothreitol
-
80% residual activity at 1 mM
ebselen
-
almost complete inhibition at 0.02 mM
F-
-
competitive vs. cytochrome b5, reversible by dilution
Hemin
-
-
I-
-
competitive vs cytochrome b5, reversible by dilution
Inositol hexaphosphate
-
-
iodoacetamide
iodoacetate
-
27.3% residual activity at 1 mM
iodoacetic acid
-
5 mM, complete inhibition
K+ high ionic strength
-
luteolin
-
-
luteolin-7-O-glucoside
-
-
Mepacrin
-
-
Mersalyl
-
complete inhibition at 1.0 mM
MgCl2
-
78.1 mM, 50% inhibition, competitive vs. cytochrome b5
morin
-
-
myricetin
N-ethylmaleimide
NaCN
-
91.4% residual activity at 1 mM
nitric oxide
-
-
p-chloromercuribenzoate
p-hydroxymercuribenzoate
para-chloromercuribenzenesulfonate
-
Pentachlorophenol
-
-
peroxynitrite
-
-
phosphate
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competitive inhibition
Phytohemagglutinin
-
-
-
Proflavin
propylthiouracil
-
complete inhibition at 0.5 mM
quercetin
quercitrin
-
-
rutin
-
-
succinate
-
-
taurodeoxycholate
Thenoyltrifluoroacetone
-
-
Tris
-
reduction of cytochrome b5
Wheat germ agglutinin
-
-
-
ZINC39395747
-
-
additional information
-
ACTIVATING COMPOUND
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
9-Amino-1,2,3,4-tetrahydroacridine
-
activation
Detergents
spermine
-
activation
KM VALUE [mM]
SUBSTRATE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
0.83
2,6-dichlorophenolindophenol
-
-
0.0419
aquacobalamin
-
-
0.63
benzamidoxime
-
pH 7.4
0.000007 - 0.08199
cytochrome b5
-
0.007
cytochrome c
-
cytochrome b5/cytochrome b5 reductase FAD-domain fusion protein
0.36
dapsone hydroxylamine
-
pH 7.4
0.0006 - 4.35
ferricyanide
0.01 - 0.013
ferricytochome b5
-
0.0008 - 0.125
ferricytochrome b5
0.001 - 0.107
ferrocytochrome b5
0.008
methemoglobin-ferrocyanide complex
-
-
-
0.25
N-hydroxy-2-amino-1-methyl-6-phenylimidazol[4,5-b]pyridine
-
pH 7.4
0.22
N-Hydroxy-4-aminobiphenyl
-
pH 7.4
0.00016 - 3.32
NADH
0.001 - 14
NADPH
0.328
oxidized 2,6-dichlorophenolindophenol
-
at pH 6.4 and 25°C
0.36
sulfamethoxazole hydroxylamine
-
pH 7.4
0.025 - 0.089
testosterone
-
depending on phosphate concentration
additional information
additional information
-
detailed analysis of biphasic rate of reduction of cytochrome b5 in membranes. The initial rapid phase is completed within 10 msec and over 90% of cytochrome b5 are reduced in 40 msec. Evaluation of data in terms of two-dimensional random walk model
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TURNOVER NUMBER [1/s]
SUBSTRATE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
50.2
2,6-dichlorophenolindophenol
-
-
1 - 877
cytochrome b5
-
8.3
cytochrome c
-
cytochrome b5/cytochrome b5 reductase FAD-domain fusion protein
12 - 1241
ferricyanide
33 - 417
ferricytochome b5
-
14 - 911
ferricytochrome b5
10 - 600
ferrocytochrome b5
0.733 - 1150
NADH
3 - 550
NADPH
kcat/KM VALUE [1/mMs-1]
SUBSTRATE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
25530 - 46610
ferricyanide
80700 - 120500
ferricytochrome b5
880 - 68320
NADH
Ki VALUE [mM]
INHIBITOR
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
0.08
ADP
-
-
0.07
apocynin
-
at pH 7.4 and 37°C
0.00021
myricetin
-
versus NADH, pH 7.5, 24-25°C
additional information
additional information
-
inhibition kinetics
-
IC50 VALUE [mM]
INHIBITOR
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
0.0045
(+)-catechin
Bos taurus
-
pH 7.5, 22°C
0.0098
(+)-taxifolin
Bos taurus
-
pH 7.5, 24-25°C
0.0032
(-)-epicatechin
Bos taurus
-
pH 7.5, 22°C
0.00914
6-([[(2R)-2,3-dihydro-1,3-benzoxazol-2-yl]sulfanyl]methyl)-2-sulfanylidene-2,3-dihydropyrimidin-4(1H)-one
Homo sapiens
-
at pH 7.5 and 37°C
0.0108
6-[(phenylsulfanyl)methyl]-2-sulfanylidene-2,3-dihydropyrimidin-4(1H)-one
Homo sapiens
-
at pH 7.5 and 37°C
0.036
apigenin
Bos taurus
-
pH 7.5, 22°C
0.00011
luteolin
Bos taurus
-
pH 7.5, 22°C
0.0024
luteolin-7-O-glucoside
Bos taurus
-
pH 7.5, 22°C
0.00081
morin
Bos taurus
-
pH 7.5, 22°C
0.00037 - 0.0015
myricetin
0.2794
propylthiouracil
Homo sapiens
-
at pH 7.5 and 37°C
0.0011
quercetin
Bos taurus
-
pH 7.5, 22°C
0.0012
quercitrin
Bos taurus
-
pH 7.5, 22°C
0.057
rutin
Bos taurus
-
pH 7.5, 22°C