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Literature summary for 1.16.1.10 extracted from

  • Solti, A.; Mueller, B.; Czech, V.; Sarvari, E.; Fodor, F.
    Functional characterization of the chloroplast ferric chelate oxidoreductase enzyme (2014), New Phytol., 202, 920-928 .
    View publication on PubMed

KM Value [mM]

KM Value [mM] KM Value Maximum [mM] Substrate Comment Organism Structure
additional information
-
additional information FCR activity of inner envelope of chloroplast vesicles isolated from Fe-deficient plants shows clear biphasic kinetics. Using NADPH, biphasic saturation kinetics are measured with the first saturation found at KM = 0.0046 mM Fe(III)-EDTA, and the second saturation found at KM = 0.0557 mM Fe(III)-EDTA. In the presence of NADH, the saturation kinetics is monophasic, the sole saturation reaction rate is significantly lower, and the KM value of the reaction is significantly higher with 0.0834 mM Fe(III)-EDTA compared to the second saturation measured with NADPH. In vesicles isolated from Fe-sufficient plants, the affinity of the enzyme does not change with KM = 0.0042mM Fe(III)-EDTA. The second, low-affinity saturation point, KM = 0.155 mM Fe(III)-EDTA is significantly higher than that in Fe-sufficient plants, with a reaction rate that is also somewhat higher than in the envelope of chloroplast membranes of Fe-sufficient plants Beta vulgaris

Localization

Localization Comment Organism GeneOntology No. Textmining
chloroplast envelope
-
Beta vulgaris 9941
-

Natural Substrates/ Products (Substrates)

Natural Substrates Organism Comment (Nat. Sub.) Natural Products Comment (Nat. Pro.) Rev. Reac.
2 Fe(III)-siderophore + NADPH Beta vulgaris
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2 Fe(II)-siderophore + NADP+ + H+
-
?

Organism

Organism UniProt Comment Textmining
Beta vulgaris
-
cv. Orbis
-

Purification (Commentary)

Purification (Comment) Organism
isolation of chloroplasts and chloroplast envelope membranes from leaves. Before isolating chloroplasts, the chlorophyll content and photosynthetic activity of Fe-sufficient and Fe-deficient leaves are measured, as indicators of the iron nutrition status Beta vulgaris

Source Tissue

Source Tissue Comment Organism Textmining
leaf
-
Beta vulgaris
-

Substrates and Products (Substrate)

Substrates Comment Substrates Organism Products Comment (Products) Rev. Reac.
2 Fe(III)-siderophore + NADH
-
Beta vulgaris 2 Fe(II)-siderophore + NAD+ + H+
-
?
2 Fe(III)-siderophore + NADPH
-
Beta vulgaris 2 Fe(II)-siderophore + NADP+ + H+
-
?
additional information reduction of Fe(III)-ethylenediaminetetraacetic acid is monitored spectrophotometrically by the Fe(II)-bathophenanthroline disulfonate complex formation for enzyme activity determination Beta vulgaris ?
-
?

Synonyms

Synonyms Comment Organism
cFRO
-
Beta vulgaris
chloroplast ferric chelate oxidoreductase
-
Beta vulgaris
FCR
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Beta vulgaris
ferric chelate oxidoreductase
-
Beta vulgaris

pH Optimum

pH Optimum Minimum pH Optimum Maximum Comment Organism
6.5 7
-
Beta vulgaris

pH Range

pH Minimum pH Maximum Comment Organism
5.5 8 activity range measured, inactivation at pH above 8.0, the enzyme is active at pH below pH 5.5 Beta vulgaris

Cofactor

Cofactor Comment Organism Structure
additional information the reaction rate is over 2.5times higher with NADPH than with NADH Beta vulgaris
NADH
-
Beta vulgaris
NADPH preferred, natural cofactor Beta vulgaris

General Information

General Information Comment Organism
physiological function iron has an essential role in the biosynthesis of chlorophylls and redox cofactors, and thus chloroplast iron uptake is a process of special importance. The chloroplast ferric chelate oxidoreductase (cFRO) has a crucial role in this process Beta vulgaris