Ligand imidazole

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Basic Ligand Information

Molecular Structure
Picture of imidazole (click for magnification)
Molecular Formula
BRENDA Name
InChIKey
C3H4N2
imidazole
RAXXELZNTBOGNW-UHFFFAOYSA-N
Synonyms:
Imidazol

Roles as Enzyme Ligand

In Vivo Substrate in Enzyme-catalyzed Reactions (1 result)

EC NUMBER
PROVEN IN VIVO REACTION
REACTION DIAGRAM
LITERATURE
ENZYME 3D STRUCTURE
acetyl-CoA + imidazole = CoA + N-acetylimidazole
show the reaction diagram
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Substrate in Enzyme-catalyzed Reactions (7 results)

EC NUMBER
REACTION
REACTION DIAGRAM
LITERATURE
ENZYME 3D STRUCTURE
imidazole + O2 + reduced putidaredoxin = ?
show the reaction diagram
S-adenosyl-L-methionine + imidazole = ?
show the reaction diagram
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nicotinic acid mononucleotide + imidazole = nicotinate + ?
show the reaction diagram
thiamine + imidazole = 4-methyl-5-(2-hydroxyethyl)-thiazole + 5-(1H-imidazol-1-yl-methyl)-2-methylpyrimidin-4-amine
show the reaction diagram
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UDP-glucose + imidazole = uridine 5'-phosphoimidazole + alpha-D-glucose 1-phosphate
show the reaction diagram
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Product in Enzyme-catalyzed Reactions (12 results)

EC NUMBER
REACTION
REACTION DIAGRAM
LITERATURE
ENZYME 3D STRUCTURE
trans-cinnamoyl imidazole + H2O = trans-cinnamate + imidazole
show the reaction diagram
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N-trans-cinnamoyl imidazole + H2O = (E)-cinnamate + imidazole
show the reaction diagram
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Activator in Enzyme-catalyzed Reactions (26 results)

EC NUMBER
COMMENTARY
LITERATURE
ENZYME 3D STRUCTURE
in vitro stimulation of prostaglandin F2alpha and D2 production
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luminescence activity of BFP-aq 1s stimulated 1.5- to 2fold by imidazole at concentrations of 30-300 mM. Imidazole has no effect on the binding affinity of coelenterazine and may act as a catalytic base
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at 0.1 mM Fe2+ 4 mM ATP inhibits enzyme activity. At increased Fe2+ concentrations ATP stimulates with a maximum at 64 mM ATP for 1.0 mM Fe2+; stimulates at 1.0 mM Fe2+
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alphaH44A mutant, works as catalytic base
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activates recombinant wild-type enzyme and mutant V311M
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in complex with Cu2+ enhances activity
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unprotonated imidazole causes a 5fold increase in maximal velocity
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stimulates activity of the mutant up to 5.5fold
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5 mM, activity of both isoenzymes is modestly enhanced
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strongly increases activity
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20 mM, activates enzyme activity by 8%
activation
-
activating ability in decreasing order: histamine, imidazole, L-histidine, D-histidine
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0.2 M, accelerates 5fold
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imidazole buffers promote the enzyme activity
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enhances activity of wild-type enzyme markedly, enhances Y171A somewhat and fails to enhance Y171F. When stoichiometric levels of tyrosine are included in the reaction with imidazole, wild-type enzyme as well as mutant enzymes are stimulated. Degree of stimulation of wild-type enzyme continues to exceed that of the mutants
addition at concentrations below that of Mg2+ increases the activity
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Inhibitor in Enzyme-catalyzed Reactions (100 results)

EC NUMBER
COMMENTARY
LITERATURE
ENZYME 3D STRUCTURE
; increasing the amount of imidazole in the reaction mixture with purified RDH-E2 from 25 to 225mM significantly decreases RDH-E2 activity
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activity is reduced down to 32% in the presence of 1 mM imidazole and addition of 250 mM results in complete inactivity
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1 mM, 32% inhibition
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175 mM,pH 7.0, 74% inhibition
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1 mM, 20% inhibition
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48% residual activity at 100 mM
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enzyme shows a decrease in its activity with increasing imidazole concentration, approximately 50% activity is lost in the presence of 0.8 M imidazole
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0.18 mM, 24% inhibition of the activity with quercetin, 81% inhibition of the activity with o-dianisidine, isoenzyme POX II; 0.18 mM, 72% inhibition of the activity with quercetin, 97% inhibition of the activity with o-dianisidine, isoenzyme POX I
negatively cooperative or competitive
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presence results in a reversible inactivation of the enzyme
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imidazoles coordinate the heme iron atom, impair ferric heme reduction, produce uncompetitive inhibition with respect to O2 and NO and inhibit NO metabolism
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at 20 mM, only half of P450SMO activity remains
20% inhibition at 1 mM
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0.1 mM, complete inhibition
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1 mM, 14% loss of activity
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the demethylation of cob(I)inamide reaction is inhibited by imidazole. Imidazole does not inhibit methyltransfer from methylcob(III)alamin to coenzyme M at 10 mM
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weak inhibition of wild-type enzyme
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wild-type
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weak, 25% inhibition at 0.4 M
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12.1 mM, 76% inhibition of the reaction with adenine and deoxycytidine
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uncompetitive inhibition
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competitive
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Zn2+ enhances kinetic inhibition by imidazole 560fold due to formation of ternary complexes with enzyme
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90-30% loss of activity, thiobenzyl benzyloxycarbonyl-L-lysinate as substrate
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hemoglobin hydrolysis inhibited, cleavage of small synthetic peptide and ester substrates enhanced
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10 mM: 99% of maximal activity
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leads to a complete elimination of enzyme activity towards D-gluconate
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imidazole may coordinate to ferric heme iron, triggering a heme-iron transition from high spin state to low spin state
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noncompetitive
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non-competitive
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imidazole stacks on the bound heme and inhibits heme oxidation by H2O2, heme dissociation by DTT, and catalytic activity
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0.001 mM, 75% inhibition
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Metals and Ions (1 result)

EC NUMBER
COMMENTARY
LITERATURE
ENZYME 3D STRUCTURE
about 2fold activation
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3D Structure of Enzyme-Ligand-Complex (PDB) (416 results)

EC NUMBER
ENZYME 3D STRUCTURE

Enzyme Kinetic Parameters

kcat Value (Turnover Number) (4 results)

EC NUMBER
TURNOVER NUMBER [1/S]
TURNOVER NUMBER MAXIMUM [1/S]
COMMENTARY
LITERATURE

KM Value (5 results)

EC NUMBER
KM VALUE [MM]
KM VALUE MAXIMUM [MM]
COMMENTARY
LITERATURE
125
-
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Ki Value (16 results)

EC NUMBER
KI VALUE [MM]
KI VALUE MAXIMUM [MM]
COMMENTARY
LITERATURE
0.0002
-
-
0.05
-
-
6
-
-
5
-
pH 9.8, 25°C

References & Links

Links to other databases for imidazole

ChEBI
PubChem
ChEBI
PubChem