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Literature summary for 1.1.1.86 extracted from

  • Dumas, R.; Job, D.; Ortholand, J.Y.; Emeric, G.; Greiner, A.; Douce, R.
    Isolation and kinetic properties of acetohydroxy acid isomeroreductase from spinach (Spinacia oleracea) chloroplasts overexpressed in Escherichia coli (1992), Biochem. J., 288, 865-874.
No PubMed abstract available

Cloned(Commentary)

Cloned (Comment) Organism
expression in Escherichia coli Spinacia oleracea

Inhibitors

Inhibitors Comment Organism Structure
2,3-dihydroxy-3-isovalerate
-
Spinacia oleracea
2-hydroxy-2-methyl-3-oxopentanoate
-
Spinacia oleracea
NADP+ product inhibition Spinacia oleracea

KM Value [mM]

KM Value [mM] KM Value Maximum [mM] Substrate Comment Organism Structure
0.0017
-
NADPH pH 8.2, 30°C Spinacia oleracea
0.01
-
2-acetolactate pH 8.2, 30°C Spinacia oleracea
0.01
-
2-aceto-2-hydroxybutyrate pH 8.2, 30°C Spinacia oleracea
0.101
-
NADH pH 8.2, 30°C Spinacia oleracea

Localization

Localization Comment Organism GeneOntology No. Textmining
chloroplast
-
Spinacia oleracea 9507
-

Metals/Ions

Metals/Ions Comment Organism Structure
Mg2+ required Spinacia oleracea
Mg2+ Km for Mg2+: 0.0045 mM, at pH 8.2, 30°C Spinacia oleracea

Molecular Weight [Da]

Molecular Weight [Da] Molecular Weight Maximum [Da] Comment Organism
56850
-
2 * 56850, calculation from acid sequence Spinacia oleracea
57000
-
2 * 57000, SDS-PAGE Spinacia oleracea
115000
-
recombinant enzyme expressed in E. coli, gel filtration Spinacia oleracea
205000
-
non-denaturing SDS-PAGE Spinacia oleracea

Natural Substrates/ Products (Substrates)

Natural Substrates Organism Comment (Nat. Sub.) Natural Products Comment (Nat. Pro.) Rev. Reac.
2-acetolactate + NADPH Spinacia oleracea enzyme of branched chain amino acid synthesis 2,3-dihydroxy-3-methylbutanoate + NADP+
-
r

Organism

Organism UniProt Comment Textmining
Spinacia oleracea
-
overexpressed in Escherichia coli
-

Purification (Commentary)

Purification (Comment) Organism
recombinant enzyme from Escherichia coli Spinacia oleracea

Source Tissue

Source Tissue Comment Organism Textmining
leaf
-
Spinacia oleracea
-

Specific Activity [micromol/min/mg]

Specific Activity Minimum [µmol/min/mg] Specific Activity Maximum [µmol/min/mg] Comment Organism
5
-
-
Spinacia oleracea

Substrates and Products (Substrate)

Substrates Comment Substrates Organism Products Comment (Products) Rev. Reac.
2-acetolactate + NADH + H+
-
Spinacia oleracea 2,3-dihydroxy-3-methylbutanoate + NAD+ + H+
-
r
2-acetolactate + NADPH enzyme of branched chain amino acid synthesis Spinacia oleracea 2,3-dihydroxy-3-methylbutanoate + NADP+
-
r
NADPH + 2-aceto-2-hydroxybutyrate
-
Spinacia oleracea NADP+ + ?
-
?
NADPH + 2-acetolactate
-
Spinacia oleracea NADP+ + 3-hydroxy-3-methyl-2-oxobutyrate
-
?

Subunits

Subunits Comment Organism
dimer 2 * 57000, SDS-PAGE Spinacia oleracea
dimer 2 * 56850, calculation from acid sequence Spinacia oleracea

pH Optimum

pH Optimum Minimum pH Optimum Maximum Comment Organism
8.2
-
-
Spinacia oleracea

Cofactor

Cofactor Comment Organism Structure
NADPH
-
Spinacia oleracea

Ki Value [mM]

Ki Value [mM] Ki Value maximum [mM] Inhibitor Comment Organism Structure
0.005
-
NADP+ pH 8.2, 30°C, NADPH as variable substrate, 0.2 mM (2S)-2-acetolactate as fixed substrate Spinacia oleracea
0.0075
-
NADP+ pH 8.2, 30°C, NADPH as variable substrate, 0.2 mM (2S)-2-aceto-2-hydroxybutanoate as fixed substrate Spinacia oleracea
0.095
-
2,3-dihydroxyisovalerate pH 8.2, 30°C, (2S)-2-acetolactate as variable substrate, 0.250 mM NADPH as fixed substrate Spinacia oleracea
0.145
-
2,3-dihydroxy-3-isovalerate pH 8.2, 30°C, (2S)-2-aceto-2-hydroxybutanoate as variable substrate, 0.250 mM NADPH as fixed substrate Spinacia oleracea
0.225
-
NADP+ pH 8.2, 30°C, (2S)-2-aceto-2-hydroxybutanoate as variable substrate, 0.075 mM NADPH as fixed substrate Spinacia oleracea
0.24
-
2-hydroxy-2-methyl-3-oxopentanoate pH 8.2, 30°C, (2S)-2-aceto-2-hydroxybutanoate as variable substrate, 0.075 mM NADPH as fixed substrate Spinacia oleracea
0.245
-
2-hydroxy-2-methyl-3-oxopentanoate pH 8.2, 30°C, (2S)-2-acetolactate as variable substrate, 0.075 mM NADPH as fixed substrate Spinacia oleracea
0.33
-
NADP+ pH 8.2, 30°C, (2S)-2-acetolactate as variable substrate, 0.075 mM NADPH as fixed substrate Spinacia oleracea
0.935
-
2,3-dihydroxyisovalerate pH 8.2, 30°C, NADPH as variable substrate, 0.2 mM (2S)-2-acetolactate as fixed substrate Spinacia oleracea
1.5
-
2,3-dihydroxyisovalerate pH 8.2, 30°C, NADPH as variable substrate, 0.2 mM (2S)-2-aceto-2-hydroxybutanoate as fixed substrate Spinacia oleracea
1.7
-
2-hydroxy-2-methyl-3-oxopentanoate pH 8.2, 30°C, NADPH as variable substrate, 0.2 mM (2S)-2-acetolactate as fixed substrate Spinacia oleracea
3.6
-
2-hydroxy-2-methyl-3-oxopentanoate pH 8.2, 30°C, NADPH as variable substrate, 0.2 mM (2S)-2-aceto-2-hydroxybutanoate as fixed substrate Spinacia oleracea