Ligand protoporphyrin IX

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Basic Ligand Information

Molecular Structure
Picture of protoporphyrin IX (click for magnification)
Molecular Formula
BRENDA Name
InChIKey
C34H34N4O4
protoporphyrin IX
KSFOVUSSGSKXFI-UJJXFSCMSA-N
Synonyms:
protoporphyrin, protoporphyrin-IX


Show all pahtways known for Show all BRENDA pathways known for protoporphyrin IX

Roles as Enzyme Ligand

In Vivo Substrate in Enzyme-catalyzed Reactions (17 results)

EC NUMBER
PROVEN IN VIVO REACTION
REACTION DIAGRAM
LITERATURE
ENZYME 3D STRUCTURE
protoporphyrin IX + ascorbate + O2 = hematinic acid + a tripyrrole + Fe3+
show the reaction diagram
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In Vivo Product in Enzyme-catalyzed Reactions (11 results)

EC NUMBER
PROVEN IN VIVO REACTION
REACTION DIAGRAM
LITERATURE
ENZYME 3D STRUCTURE
protoporphyrinogen IX + O2 = protoporphyrin IX + H2O
show the reaction diagram
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protoheme + H+ = protoporphyrin + Fe2+
show the reaction diagram
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Substrate in Enzyme-catalyzed Reactions (85 results)

EC NUMBER
REACTION
REACTION DIAGRAM
LITERATURE
ENZYME 3D STRUCTURE
protoporphyrin IX + ascorbate + O2 = hematinic acid + a tripyrrole + Fe3+
show the reaction diagram
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S-adenosyl-L-methionine + protoporphyrin = S-adenosyl-L-homocysteine + protoporphyrin monomethyl ester
show the reaction diagram
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Product in Enzyme-catalyzed Reactions (19 results)

EC NUMBER
REACTION
REACTION DIAGRAM
LITERATURE
ENZYME 3D STRUCTURE
protoporphyrinogen IX + O2 = protoporphyrin IX + H2O
show the reaction diagram
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Activator in Enzyme-catalyzed Reactions (3 results)

EC NUMBER
COMMENTARY
LITERATURE
ENZYME 3D STRUCTURE

Inhibitor in Enzyme-catalyzed Reactions (13 results)

EC NUMBER
COMMENTARY
LITERATURE
ENZYME 3D STRUCTURE
inhibition of HemF
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enzyme activity decreases with increasing concentrations, reaching a 33% inhibition at the vivo concentration of porphyrin, 0.00185 mM, and 0.014 mM porphobilinogen
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3D Structure of Enzyme-Ligand-Complex (PDB) (12 results)

Enzyme Kinetic Parameters

kcat Value (Turnover Number) (33 results)

EC NUMBER
TURNOVER NUMBER [1/S]
TURNOVER NUMBER MAXIMUM [1/S]
COMMENTARY
LITERATURE
0.0002
-
concentrations between 1 and 30 microM in the presence of 200 nM enzyme
0.4
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pH 7.2, 30°C. The Km-value for protoporphyrin IX is the same independent of whether Zn2+ or Fe2+ is used in the reaction

KM Value (55 results)

EC NUMBER
KM VALUE [MM]
KM VALUE MAXIMUM [MM]
COMMENTARY
LITERATURE
0.053
-
concentrations between 1 and 30 microM in the presence of 200 nM enzyme
0.008
-
pH 7.2, 30°C. The Km-value for protoporphyrin IX is the same independent of whether Zn2+ or Fe2+ is used in the reaction

Ki Value (3 results)

EC NUMBER
KI VALUE [MM]
KI VALUE MAXIMUM [MM]
COMMENTARY
LITERATURE
0.0025
-
-

IC50 Value (3 results)

EC NUMBER
IC50 VALUE
IC50 VALUE MAXIMUM
COMMENTARY
LITERATURE
0.00055
-
at pH 5.5 and 37°C

References & Links

Links to other databases for protoporphyrin IX

ChEBI
PubChem
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PubChem