Information on EC 1.11.2.2 - myeloperoxidase

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The expected taxonomic range for this enzyme is: Eukaryota

EC NUMBER
COMMENTARY hide
1.11.2.2
-
RECOMMENDED NAME
GeneOntology No.
myeloperoxidase
-
REACTION
REACTION DIAGRAM
COMMENTARY hide
ORGANISM
UNIPROT
LITERATURE
Cl- + H2O2 + H+ = HClO + H2O
show the reaction diagram
-
-
-
-
SYSTEMATIC NAME
IUBMB Comments
chloride:hydrogen-peroxide oxidoreductase (hypochlorite-forming)
Contains calcium and covalently bound heme (proximal ligand histidine). It is present in phagosomes of neutrophils and monocytes, where the hypochlorite produced is strongly bactericidal. It differs from EC 1.11.1.10 chloride peroxidase in its preference for formation of hypochlorite over the chlorination of organic substrates under physiological conditions (pH 5-8). Hypochlorite in turn forms a number of antimicrobial products (Cl2, chloramines, hydroxyl radical, singlet oxygen). MPO also oxidizes bromide, iodide and thiocyanate. In the absence of halides, it oxidizes phenols and has a moderate peroxygenase activity toward styrene.
ORGANISM
COMMENTARY hide
LITERATURE
UNIPROT
SEQUENCE DB
SOURCE
Armoracia sp.
-
-
-
Manually annotated by BRENDA team
horse, myeloperoxidase
-
-
Manually annotated by BRENDA team
-
-
-
Manually annotated by BRENDA team
japanese radish, 18 isozymes, here JRPa and JRPc
-
-
Manually annotated by BRENDA team
-
-
-
Manually annotated by BRENDA team
GENERAL INFORMATION
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
malfunction
-
mice deficient in myeloperoxidase are more likely than wild type mice to die from infection by polymicrobial sepsis
physiological function
SUBSTRATE
PRODUCT                       
REACTION DIAGRAM
ORGANISM
UNIPROT
COMMENTARY
(Substrate) hide
LITERATURE
(Substrate)
COMMENTARY
(Product) hide
LITERATURE
(Product)
Reversibility
r=reversible
ir=irreversible
?=not specified
(-)-epicatechin + H2O2
? + H2O
show the reaction diagram
-
-
-
-
?
1-acetyl-4-(methylsulfanyl)benzene + H2O2 + H+
?
show the reaction diagram
-
-
-
-
?
1-chloro-4-(methylsulfanyl)benzene + H2O2 + H+
?
show the reaction diagram
-
-
-
-
?
1-methoxy-4-(methylsulfanyl)benzene + H2O2 + H+
?
show the reaction diagram
-
-
-
-
?
1-methyl-4-(methylsulfanyl)benzene + H2O2 + H+
?
show the reaction diagram
-
-
-
-
?
1-nitro-4-(methylsulfanyl)benzene + H2O2 + H+
?
show the reaction diagram
-
-
-
-
?
1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine + Br- + H2O2
?
show the reaction diagram
-
the formation of bromohydrins by the MPO-H2O2-bromide system using physiological chloride concentrations occurs only at acidic pH values but not at pH 7.4
-
-
?
1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine + Cl- + H2O2
?
show the reaction diagram
-
the formation of chlorohydrins by the MPO-H2O2-chloride system using physiological chloride concentrations occurs only at acidic pH values but not at pH 7.4
-
-
?
2,2'-azino-bis-(3-ethylbenzthiazole-6-sulfonic acid) + H2O2
? + H2O
show the reaction diagram
-
both properoxinectin and peroxinectin are catalytically active as peroxidases
-
-
?
2-phenylenediamine + H2O2
?
show the reaction diagram
-
-
-
-
?
3,4-dihydroxyphenylacetic acid + H2O2
? + H2O
show the reaction diagram
4-(methylsulfanyl)aniline + H2O2 + H+
?
show the reaction diagram
-
-
-
-
?
4-tolyl methyl sulfide + H2O2 + H+
?
show the reaction diagram
-
-
-
-
?
5-cyanoindole + H2O2
?
show the reaction diagram
-
-
-
-
?
5-hydroxytryptamine + H2O2
?
show the reaction diagram
-
-
-
-
?
5-nitroindole + H2O2
?
show the reaction diagram
-
-
-
-
?
ascorbate + H2O2
?
show the reaction diagram
-
-
-
-
?
benzothiophene + H2O2 + H+
?
show the reaction diagram
-
-
-
-
?
benzyl methyl sulfide + H2O2 + H+
?
show the reaction diagram
-
-
-
-
?
Br- + H2O2
?
show the reaction diagram
Br- + H2O2
HBrO + H2O
show the reaction diagram
-
at physiological concentrations of chloride and bromide, hypobromous acid can be a major oxidant produced by myeloperoxidase
-
-
?
Br- + H2O2 + H+
?
show the reaction diagram
-
-
-
-
?
Br- + H2O2 + H+
HBrO + H2O
show the reaction diagram
-
-
-
-
?
catechol + H2O2
? + H2O
show the reaction diagram
chloride + H2O2
hypochlorous acid + H2O
show the reaction diagram
-
-
-
-
?
Cl- + H2O2
?
show the reaction diagram
-
-
-
?
Cl- + H2O2
HClO + H2O
show the reaction diagram
Cl- + H2O2
HOCl + H2O
show the reaction diagram
-
-
-
?
Cl- + H2O2 + chloroacetonitrile
HClO + H2O + cyanide
show the reaction diagram
-
chloride ion (Cl-) is the dominant electron donor, chloroacetonitrile is activated to cyanide by myeloperoxidase/H2O2/Cl- system in vitro
-
-
?
Cl- + H2O2 + H+
HClO + H2O
show the reaction diagram
Cl- + H2O2 + H+ + taurine + H+
taurine monochloroamine + 2 H2O
show the reaction diagram
-
the taurine chlorination reaction mediated by the myeloperoxidase system in vivo may involve an enzyme intermediate species rather than free HOCl
-
-
?
donor + H2O2
oxidized donor + H2O
show the reaction diagram
donor + HOCl
oxidized donor + Cl-
show the reaction diagram
dopamine + H2O2
? + H2O
show the reaction diagram
guaiacol + H2O2
?
show the reaction diagram
-
at neutral pH MPO has higher affinity to peroxidase substrate guaiacol
-
-
?
guaiacol + H2O2
tetraguaiacol + H2O
show the reaction diagram
I- + H2O2
?
show the reaction diagram
I- + H2O2 + H+
?
show the reaction diagram
-
-
-
-
?
I- + H2O2 + H+
HIO + H2O
show the reaction diagram
indole + H2O2
?
show the reaction diagram
-
-
-
-
?
low-density lipoprotein + Cl- + H2O2
? + H2O
show the reaction diagram
-
-
enzyme produces oxidative modifications of the protein moiety of low density lipoproteins
-
?
monochlorodimedon + Cl-
dichlorodimedon
show the reaction diagram
-
-
-
-
?
monochlorodimedone + H2O2
?
show the reaction diagram
-
-
-
-
?
monochlorodimedone + H2O2
dichlorodimedone + H2O
show the reaction diagram
-
-
-
-
?
myricitrin + H2O2
? + H2O
show the reaction diagram
-
myeloperoxidase is less efficient at oxidizing myricitrin at higher concentrations (0.05 mM) of H2O2
-
-
?
NADH + O2 + H+
NAD+ + H2O2
show the reaction diagram
-
myeloperoxidase is capable of catalyzing an oscillating peroxidase-oxidase reaction, when chloride is present in the reaction mixture
-
-
?
nitric oxide + H2O2
?
show the reaction diagram
-
-
-
-
?
nitrite + H2O2
?
show the reaction diagram
-
-
-
-
?
nitrite + L-tyrosine + H2O2 + H+
?
show the reaction diagram
-
poor substrate for myeloperoxidase, but free tyrosine facilitates nitration of tyrosyl residues by acting as a cosubstrate in the reaction
-
-
?
NO2- + H2O2
?
show the reaction diagram
-
-
-
-
?
o-dianisidine + H2O2
?
show the reaction diagram
o-dianisidine + H2O2
oxidized o-dianisidine + H2O
show the reaction diagram
-
-
-
-
?
phenyl propan-2-yl sulfide + H2O2 + H+
?
show the reaction diagram
-
-
-
-
?
quercetin + H2O2
oxidized quercetin + H2O
show the reaction diagram
-
-
-
-
?
SCN- + H2O2
?
show the reaction diagram
-
-
-
?
SCN- + H2O2
OSCN- + H2O
show the reaction diagram
serotonin + H2O2
serotonin dimer + H2O
show the reaction diagram
-
favoured substrate of myeloperoxidase, only ascorbate blocks oxidation of serotonin
-
-
?
serotonin + superoxide
tryptamine-4,5-dione + H2O
show the reaction diagram
-
-
-
-
?
taurine + Cl- + H2O2
taurine chloramine + H2O
show the reaction diagram
-
-
-
-
?
tetramethylbenzidine + H2O2
?
show the reaction diagram
-
-
-
-
?
tetramethylbenzidine + H2O2 + H+
?
show the reaction diagram
-
-
-
-
?
thioanisole + H2O2 + H+
?
show the reaction diagram
-
-
-
-
?
thiocyanate + H2O2
hypothiocyanite + H2O
show the reaction diagram
-
-
-
-
?
thiocyanate + H2O2 + H+
?
show the reaction diagram
-
-
-
-
?
thiocyanate + H2O2 + H+
hypothiocyanate + H2O
show the reaction diagram
-
-
-
-
?
thiocyanate + H2O2 + H+
hypothiocyanite + H2O
show the reaction diagram
tryptamine + H2O2
?
show the reaction diagram
-
-
-
-
?
tyrosine + H2O2
?
show the reaction diagram
-
-
-
-
?
tyrosine + H2O2
dityrosine + H2O
show the reaction diagram
-
-
-
-
?
urate + H2O2
5-hydroxyisourate + H2O
show the reaction diagram
-
-
-
-
?
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
ascorbate + H2O2
?
show the reaction diagram
-
-
-
-
?
Br- + H2O2
?
show the reaction diagram
-
-
-
-
?
Cl- + H2O2
HClO + H2O
show the reaction diagram
Cl- + H2O2 + H+
HClO + H2O
show the reaction diagram
Cl- + H2O2 + H+ + taurine + H+
taurine monochloroamine + 2 H2O
show the reaction diagram
-
the taurine chlorination reaction mediated by the myeloperoxidase system in vivo may involve an enzyme intermediate species rather than free HOCl
-
-
?
donor + H2O2
oxidized donor + H2O
show the reaction diagram
-
involved in immune defense reactions
-
-
r
donor + HOCl
oxidized donor + Cl-
show the reaction diagram
-
involved in immune defense reactions
-
-
r
I- + H2O2
?
show the reaction diagram
monochlorodimedon + Cl-
dichlorodimedon
show the reaction diagram
-
-
-
-
?
nitric oxide + H2O2
?
show the reaction diagram
-
-
-
-
?
nitrite + H2O2
?
show the reaction diagram
-
-
-
-
?
thiocyanate + H2O2
hypothiocyanite + H2O
show the reaction diagram
-
-
-
-
?
thiocyanate + H2O2 + H+
hypothiocyanite + H2O
show the reaction diagram
-
thiocyanate is a major physiological substrate of myeloperoxidase and most favoured substrate compared to chloride and bromide
-
-
?
tyrosine + H2O2
?
show the reaction diagram
-
-
-
-
?
urate + H2O2
5-hydroxyisourate + H2O
show the reaction diagram
-
-
-
-
?
additional information
?
-
COFACTOR
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
METALS and IONS
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
Ca2+
-
-
INHIBITORS
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
3-methoxybenzoic acid hydrazide
-
-
3-nitrobenzoic acid hydrazide
-
-
4'-amino-4-fluorochalcone
-
potent inhibition of the chlorinating activity. Compound is not toxic to neutrophils at concentrations below 100 microM
4'-amino-4-methylchalcone
-
potent inhibition of the chlorinating activity. Compound is not toxic to neutrophils at concentrations below 100 microM
4'-aminochalcone
-
potent inhibition of the chlorinating activity. Compound is not toxic to neutrophils at concentrations below 100 microM
4-(5-fluoro-1H-indol-3-yl)butanamide
-
reversible myeloperoxidase inhibitor, efficiently prevents enzyme-dependent LDL oxidation
4-(7-fluoro-1H-indol-3-yl)butanamide
-
-
4-aminobenzoic acid hydrazide
-
most potent inhibitor of peroxidation, it irreversibly inhibits HOCl production by the purified myeloperoxidase. With neutrophils stimulated with opsonized zymosan or phorbol myristate acetate, 4-aminobenzoic acid hydrazide inhibits HOCI production by up to 90%
4-aminobenzoic acid hydrazine
-
metabolism of chloroacetonitrile to cyanide by MPO/H2O2/Cl- system is significantly reduced by 4-amino benzoic acid hydrazine to 52.6% of control value
4-chlorobenzoic acid hydrazide
-
-
4-hydroxy-2,2,6,6-tetra-methyl-1-piperidinyloxy radical
-
tempol, 0.01 mM tempol efficiently inhibits peroxidase-mediated RNase nitration
4-hydroxy-2,2,6,6-tetramethyl piperidine-1-oxyl
-
i.e. tempol, inhibits both H2O2 consumption and taurine chlorination, reacts mostly as a reversible inhibitor of MPO by trapping it as MPO-II and the MPO-II-tempol complex, which are not within the chlorinating cycle
4-hydroxybenzoic acid hydrazide
-
-
4-methoxybenzoic acid hydrazide
-
-
5-(7-fluoro-1H-indol-3-yl)pentanamide
-
-
5-chlorotryptamine
-
IC50: 0.00073 mM
5-fluorotryptamine
-
IC50: 0.00079 mM
5-thio-2-nitrobenzoic acid
-
competitive inhibitor of myeloperoxidase
Aminotriazole
-
3 mM inhibitory
benzoic hydrazide
-
-
betanin
-
higher micromolar betanin concentrations inhibit the MPO-mediated chlorination reactions by scavenging of hypochlorous acid
catalase
-
addition of the antioxidant enzyme catalase to incubation mixtures results in 56.1% decrease in cyanide release by MPO/H2O2/Cl- system
-
cyanide
-
-
dityrosine
-
inhibits MPO-derived dityrosine formation in a dose-dependent manner
fisetin
-
-
HClO
-
-
indicaxanthin
-
at neutral pH and depending on their concentration, indicaxanthin can exhibit a stimulating and inhibitory effect on the chlorination activity of MPO, whereas at pH 5.0 only inhibitory effects are observed even at micromolar concentrations
indomethacin
-
metabolism of chloroacetonitrile to cyanide by MPO/H2O2/Cl- system is significantly reduced by indomethacin to 88.9% of control value
kaempferol
kaempferol-7-O-rhamnoside
-
8% inhibition at 0.1 mM for 10 min
luteolin
-
-
myricetin
Myricitrin
-
51% inhibition at 0.1 mM for 10 min
NaN3
-
0.3 mM inhibitory
nitrite
-
nitrite is an excellent inhibitor of the chlorination activity of myeloperoxidase, there is progressive inhibition of enzyme activity with increasing concentration of nitrite up to a maximum of 80%. Upon addition of 100 mM L-tyrosine, enzyme activity is completely restored
o-Dianisidine
-
higher concentrations than 1.54 mM inhibitory
Q3GA
-
inhibits MPO-derived dityrosine formation in a dose-dependent manner
quercetin
Salicylhydroxamic acid
-
salicylhydroxamic acid is a much poorer inhibitor of HOCI production with neutrophils stimulated with opsonized zymosan (0.2 mM is required for complete inhibition)
SCN-
-
-
serotonin
-
at higher concentrations than 0.02 mM, serotonin almost completely blocks the formation of hypochlorite
Sodium azide
Sulfide
-
at high sulfide concentrations, enzymic inhibition is observed above 0.25 mM (20% inhibition at 0.3 mM sulfide)
taxifolin
-
-
Urate
-
-
additional information
-
halides serve as substrates or inhibitors, existence of two halide binding sites that have a distinct impact on the heme iron microenvironment in myeloperoxidase
-
ACTIVATING COMPOUND
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
5-aminosalicylic acid
-
converts inactive myeloperoxidase compound II rapidly into active myeloperoxidase
ascorbic acid
betanin
-
low micromolar betanin concentrations enhance the chlorination activity of MPO at pH 7.0, increasing the betanin concentration up to 0.006 mM dramatically increases the chlorination rate of monochlorodimedon
chloride
-
in the presence of 100 mM NaCl the catalytic efficiency of MPO increases 3-4fold whatever the sulfide considered, the rate of 4-tolyl methyl sulphide oxidation enhancement is about 8fold at 120 mM NaCl
D-penicillamine
-
addition of D-penicillamine significantly enhances the rate of chloroacetonitrile oxidation and cyanide release by the myeloperoxidase/H2O2/Cl- system (17.2% increase at 5 mM)
ferrocyanide
-
converts inactive myeloperoxidase compound II into active myeloperoxidase
glutathione
-
addition of glutathione significantly enhances the rate of chloroacetonitrile oxidation and cyanide release by the myeloperoxidase/H2O2/Cl- system (24% increase at 5 mM)
indicaxanthin
-
at neutral pH and depending on their concentration, indicaxanthin can exhibit a stimulating and inhibitory effect on the chlorination activity of MPO
L-cysteine
-
addition of L-cysteine significantly enhances the rate of chloroacetonitrile oxidation and cyanide release by the myeloperoxidase/H2O2/Cl- system (45.4% increase at 5 mM)
myelin oligodendrocyte protein
-
MPO activity increases significantly in the myelin oligodendrocyte protein treated rats (0.05 mg)
-
N-acetyl-L-cysteine
-
addition of N-acetyl-L-cysteine significantly enhances the rate of chloroacetonitrile oxidation and cyanide release by the myeloperoxidase/H2O2/Cl- system (16.3% increase at 5 mM)
NaCl
-
maximal activity in the presence of 200 mM NaCl
serotonin
-
at low micromolar concentrations (below 0.02 mM), serotonin enhances hypochlorite production by both purified myeloperoxidase and neutrophils
additional information
-
hypercholesterolemia results in higher tissue MPO activities, the influences of fish oil on MPO activities are not obvious in hypercholesterolemic mice with sepsis
-
KM VALUE [mM]
SUBSTRATE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
0.016 - 0.039
1-acetyl-4-(methylsulfanyl)benzene
0.027 - 0.067
1-chloro-4-(methylsulfanyl)benzene
0.012 - 0.03
1-methoxy-4-(methylsulfanyl)benzene
0.032 - 0.04
1-methyl-4-(methylsulfanyl)benzene
0.066 - 0.076
1-nitro-4-(methylsulfanyl)benzene
0.52 - 21.9
3,4-dihydroxyphenylacetic acid
0.057 - 0.104
4-(methylsulfanyl)aniline
0.072 - 0.081
benzothiophene
0.05 - 0.083
benzyl methyl sulfide
2
Br-
-
in 100 mM phosphate buffer, pH 7.4, at 21C
1.84 - 21.1
catechol
0.089
Chloroacetonitrile
-
at pH 5.5, 37C, 0.1 mM KCl, 0.5 mM H2O2, 0.15 mM chloroacetonitrile, 5 units/ml MPO, and 0.25 mM NaOCl during an incubation period of 60 min
175
Cl-
-
in 100 mM phosphate buffer, pH 7.4, at 21C
0.64 - 136.3
dopamine
0.03 - 0.07
H2O2
0.026 - 0.041
phenyl propan-2-yl sulfide
0.25 - 0.29
SCN-
0.018 - 0.02
thioanisole
0.5
Thiocyanate
-
in 100 mM phosphate buffer, pH 7.4, at 21C
TURNOVER NUMBER [1/s]
SUBSTRATE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
4.2 - 56
1-acetyl-4-(methylsulfanyl)benzene
5 - 35
1-chloro-4-(methylsulfanyl)benzene
0.43 - 6
1-methoxy-4-(methylsulfanyl)benzene
3 - 20
1-methyl-4-(methylsulfanyl)benzene
1.8 - 5.5
1-nitro-4-(methylsulfanyl)benzene
10 - 40
4-(methylsulfanyl)aniline
1 - 1.6
benzothiophene
8
benzyl methyl sulfide
Homo sapiens
-
in the presence of 100 mM NaCl, in 50 mM acetate buffer, pH 5.0, at 20C
0.000012 - 0.000022
catechol
28.5
Cl-
Homo sapiens
-
at 21C in 50 mM sodium phosphate buffer, pH 7.4
0.0000001 - 0.0000016
dopamine
13 - 320
H2O2
0.7
nitrite
Homo sapiens
-
at 21C in 50 mM sodium phosphate buffer, pH 7.4
7.3 - 14
phenyl propan-2-yl sulfide
0.00000016 - 0.0000033
SCN-
4 - 12
thioanisole
30.5
Thiocyanate
Homo sapiens
-
at 21C in 50 mM sodium phosphate buffer, pH 7.4
IC50 VALUE [mM]
INHIBITOR
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
0.00025
4'-amino-4-fluorochalcone
0.000265
4'-aminochalcone
Homo sapiens
-
pH not specified in the publication, temperature not specified in the publication
0.000018
4-(5-fluoro-1H-indol-3-yl)butanamide
Homo sapiens
-
low density lipoprotein oxidation, pH 7.2, 37C; taurine chlorination, pH 7.2, 37C
0.000024 - 0.000026
4-(7-fluoro-1H-indol-3-yl)butanamide
0.0003
4-aminobenzoic acid hydrazide
Homo sapiens
-
at 37C, in 50 mM acetate buffer, pH 5.4
0.000034 - 0.000044
5-(7-fluoro-1H-indol-3-yl)pentanamide
0.00073
5-chlorotryptamine
Homo sapiens
-
IC50: 0.00073 mM
0.00079
5-fluorotryptamine
Homo sapiens
-
IC50: 0.00079 mM
0.00387
fisetin
Homo sapiens
-
-
0.032 - 0.05
HClO
0.00208
kaempferol
Homo sapiens
-
-
0.00422
luteolin
Homo sapiens
-
-
0.0013
nitrite
Homo sapiens
-
at 21C in 50 mM sodium phosphate buffer, pH 7.4
0.00127
quercetin
Homo sapiens
-
-
0.032
Salicylhydroxamic acid
Homo sapiens
-
at 37C, in 50 mM acetate buffer, pH 5.4
0.00663
taxifolin
Homo sapiens
-
-
0.0093
Urate
Homo sapiens
-
pH and temperature not specified in the publication
SPECIFIC ACTIVITY [µmol/min/mg]
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
additional information
-
7.9 units/mg (spent culture medium, using 2-phenylenediamine as substrate, in 100 mM sodium phosphate, pH 5.0, 150 mM NaCl, at 25C), 537 units/mg (recombinant enzyme after 67.8fold purification, using 2-phenylenediamine as substrate, in 100 mM sodium phosphate, pH 5.0, 150 mM NaCl, at 25C), 857 units/mg (recombinant enzyme after 67.8fold purification, using O-dianisidine as substrate, in 100 mM sodium phosphate, pH 5.0, 150 mM NaCl, at 25C), 800 units/mg (natural MPO, using O-dianisidine as substrate, in 100 mM sodium phosphate, pH 5.0, 150 mM NaCl, at 25C)
pH OPTIMUM
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
4.5 - 5
4.7 - 6
-
optimum pH for peroxidase activity of MPO
5.8
-
with 0.002 mM ascorbic acid as activator
7.4
-
optimum pH for chlorinating activity of MPO, at pH 7.4 chloride ions do not compete with guaiacol up to the concentration of 150 mM
pH RANGE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
5 - 7.8
-
between pH 5.0 and 7.0, myeloperoxidase converts about 90% of available hydrogen peroxide to hypochlorous acid and the remainder to hypobromous acid. Above pH 7, there is an abrupt rise in the yield of hypobromous acid. At pH 7.8, it accounts for 40% of the hydrogen peroxide
TEMPERATURE OPTIMUM
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
37
-
optimum temperature for the activation of chloroacetonitrile to cyanide by the myeloperoxidase/H2O2/Cl- system
SOURCE TISSUE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
SOURCE
-
atherosclerotic aorta
Manually annotated by BRENDA team
-
in homogenates of multiple sclerosis white matter, demyelination is associated with significantly elevated MPO activity
Manually annotated by BRENDA team
-
-
Manually annotated by BRENDA team
-
-
Manually annotated by BRENDA team
Armoracia sp.
-
-
Manually annotated by BRENDA team
LOCALIZATION
ORGANISM
UNIPROT
COMMENTARY hide
GeneOntology No.
LITERATURE
SOURCE
-
cytoplasmic granule
Manually annotated by BRENDA team
MOLECULAR WEIGHT
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
15500
-
SDS-PAGE under reducing conditions gives three bands with molecular masses of 57000, 39000 and 15000 Da, respectively
39000
-
SDS-PAGE under reducing conditions gives three bands with molecular masses of 57000, 39000 and 15000 Da, respectively
41500
-
JRPc, SDS-PAGE
54500
-
JRPa, SDS-PAGE
57000
-
SDS-PAGE under reducing conditions gives three bands with molecular masses of 57000, 39000 and 15000 Da, respectively
110000
-
dimeric mature enzyme, SDS-PAGE
150000
SUBUNITS
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
homodimer
monomer
-
1 * 70000, eosinophil peroxidase
tetramer
-
two heavy and two light subunits, SDS-PAGE
POSTTRANSLATIONAL MODIFICATION
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
glycoprotein
proteolytic modification
-
extracellular processing of properoxinectin into an active cell adhesion protein
Crystallization/COMMENTARY
ORGANISM
UNIPROT
LITERATURE
hanging drop vapor diffusion method, native MPO is crystallized with 16% (w/v) polyethylene glycol (PEG) 8000, 50 mM ammonium sulfate, 50 mM sodium acetate, 2 mM calcium acetate, and 50 mM sodium thiocyanate at 22C and pH 5.5 for 24 h
-
hanging drop vapor diffusion method, using 50 mM sodium acetate (pH 5.5), 50 mM ammonium sulfate, 2 mM calcium chloride, and 22-25% (w/v) PEG 8k, at 18C
-
pH STABILITY
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
7.2
-
the enzymic activity at pH 7.2 rapidly declines in time (from 100 ms up to 15 s)
711274
TEMPERATURE STABILITY
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
65
-
5 min without inactivation
80
-
at 80C the native dimeric MPO retains remarkable stability (50% activity left after 72 min), but hemi-MPO has already been inactivated by 50% after 4.5 min
GENERAL STABILITY
ORGANISM
UNIPROT
LITERATURE
denaturation with 3.1 M guanidinium hydrochloride
-
STORAGE STABILITY
ORGANISM
UNIPROT
LITERATURE
-20C, 0.1 M sodium acetate, pH 5.6, 0.5 M CaCl2, 0.05% w/v cetyltrimethylammonium bromide, 25% glycerol, many months, no activity loss, can be thawed and refrozen
-
Purification/COMMENTARY
ORGANISM
UNIPROT
LITERATURE
purified from raw milk
-
Q-Sepharose column chromatography, carboxymethyl-Sepharose column chromatography, chelating-Sepharose column chromatography, and Sephacryl S200 gel filtration
-
recombinant MPO
-
Cloned/COMMENTARY
ORGANISM
UNIPROT
LITERATURE
expressed in CHO cell line 24.1.7
-
expression in CHO cells
-
human recombinant unprocessed monomeric myeloperoxidase is expressed in CHO cells
-
EXPRESSION
ORGANISM
UNIPROT
LITERATURE
urate enhances MPO-dependent consumption of nitric oxide
-
APPLICATION
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
analysis
-
detection of myeloperoxidase activity in vivo by use of a paramagneitc substrate. The sensing probe is obtained by replacing the reducing substrate serotonin with 5-hydroxytryptophan. The resulting probe bis-hydroxytryptophan-gadolinium diethylenetriamine pentaacetic acid in vitro improves solubility in water, acts as a substrate, induces cross linking of proteins in the presence of myeloperoxidase,produces oxidation products which bind to plasma proteins and does not follow first order reaction kinetics. Bis-hydroxytryptophan-gadolinium diethylenetriamine pentaacetic acid is retained for up to five days in myeloperoxidase-containing sites and cleared faster than serotonin diethylenetriamine pentaacetic acid from enzyme-negative sites
medicine
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