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Literature summary for 4.2.1.33 extracted from

  • Bigelis, R.; Umbarger, H.E.
    Yeast alpha-isopropylmalate isomerase. Factors affecting enzyme stability and enzyme activity (1976), J. Biol. Chem., 251, 3545-3552.
    View publication on PubMed
Search for more literature for 4.2.1.33

General Stability

General Stability Organism
stabilized by high concentrations of glycerol and ammonium sulfate which also inhibit activity, half-life with 50% glycerol, 2.07 M ammonium sulfate, and 30% glycerol plus 830 mM ammonium sulfate: 50 h, 57 h, and 90 h, respectively, instead of 2-3 h without, stabilization probably due to changes in intramolecular interactions Saccharomyces cerevisiae

Inhibitors

Inhibitors Comment Organism Structure
(NH4)2SO4 recovery after restoration of lower ionic strength shows hysteresis effect Saccharomyces cerevisiae
1,10-phenanthroline 16% inhibition at 0.1 mM Saccharomyces cerevisiae
8-hydroxyquinolinesulfonate 16% inhibition at 0.1 mM Saccharomyces cerevisiae
K3PO4
-
 Saccharomyces cerevisiae
KCl
-
 Saccharomyces cerevisiae
KCN inactivation prevented by ammonium sulfate Saccharomyces cerevisiae
KF most potent inhibitor Saccharomyces cerevisiae
additional information inhibition at pH 4.5-5.0, reactivation at neutral pH Saccharomyces cerevisiae

KM Value [mM]

KM Value [mM] KM Value Maximum [mM] Substrate Comment Organism Structure
0.0216
-
 dimethylcitraconate
-
 Saccharomyces cerevisiae

Molecular Weight [Da]

Molecular Weight [Da] Molecular Weight Maximum [Da] Comment Organism
90000
-
 sucrose density gradient centrifugation, gel filtration Saccharomyces cerevisiae

Natural Substrates/ Products (Substrates)

Natural Substrates Organism Comment (Nat. Sub.) Natural Products Comment (Nat. Pro.) Rev. Reac.
2-isopropylmaleate + H2O Saccharomyces cerevisiae second of three reactions of leucine biosynthesis ?
-
 ?

Organism

Organism UniProt Comment Textmining
Saccharomyces cerevisiae
-
-
-

Purification (Commentary)

Purification (Comment) Organism
-
 Saccharomyces cerevisiae

Reaction

Reaction Comment Organism Reaction ID
(2R,3S)-3-isopropylmalate = 2-isopropylmaleate + H2O mechanism, equilibrium in vitro favors reaction opposite the direction of leucine biosynthesis Saccharomyces cerevisiae
a

Substrates and Products (Substrate)

Substrates Comment Substrates Organism Products Comment (Products) Rev. Reac.
2-isopropylmaleate + H2O
-
 Saccharomyces cerevisiae 3-isopropylmalate
-
 ?
2-isopropylmaleate + H2O second of three reactions of leucine biosynthesis Saccharomyces cerevisiae ?
-
 ?
3-isopropylmalate
-
 Saccharomyces cerevisiae 2-isopropylmaleate + H2O
-
 ?
dimethylcitraconate
-
 Saccharomyces cerevisiae ?
-
 ?

Subunits

Subunits Comment Organism
monomer 1*90000, SDS-PAGE Saccharomyces cerevisiae

Temperature Stability [°C]

Temperature Stability Minimum [°C] Temperature Stability Maximum [°C] Comment Organism
additional information
-
 very heat sensitive, high ionic strenght stabilizes enzyme against heat inactivation Saccharomyces cerevisiae
55
-
 half-life: 4.5 h, in stabilizing ammonium sulfate buffer Saccharomyces cerevisiae
62
-
 half-life: 1 min, in stabilizing ammonium sulfate buffer Saccharomyces cerevisiae

pH Optimum

pH Optimum Minimum pH Optimum Maximum Comment Organism
6.8
-
-
 Saccharomyces cerevisiae
7 9
-
 Saccharomyces cerevisiae

pH Stability

pH Stability pH Stability Maximum Comment Organism
6
-
 unstable at pH 7.0 or above Saccharomyces cerevisiae