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Literature summary for 5.1.3.4 extracted from

  • Johnson, A.E.; Tanner, M.E.
    Epimerization via carbon - carbon bond cleavage. L-Ribulose-5-phosphate 4-epimerase as a masked class II aldolase (1998), Biochemistry, 37, 5746-5754.
    View publication on PubMed

Cloned(Commentary)

Cloned (Comment) Organism
overexpression Escherichia coli

Protein Variants

Protein Variants Comment Organism
D76N site-directed mutants in which the putative metal ion ligand is modified: H95N, H97N, D76N. The mutant enzymes require exogenous metal ions for full activity. Their turnover numbers are greatly reduced whereas the Km-values are only moderately affected. Low levels of aldolase activity are observed with the H97N mutant, but not with D76N or the H95N mutants. The H97N mutant enzyme catalyzes the condensation of dihydroxyacetone and glycolaldehyde phosphate to produce a mixture of L-ribulose 5-phosphate and D-xylulose 5-phosphate Escherichia coli
D76N the ratio of turnover number to Km-value is 348fold lower than that of the wild-type enzyme Escherichia coli
H59N site-directed mutants in which the putative metal ion ligand is modified: H95N, H97N, D76N. The mutant enzymes require exogenous metal ions for full activity. Their turnover numbers are greatly reduced whereas the Km-values are only moderately affected. Low levels of aldolase activity are observed with the H97N mutant, but not with D76N or the H95N mutants. The H97N mutant enzyme catalyzes the condensation of dihydroxyacetone and glycolaldehyde phosphate to produce a mixture of L-ribulose 5-phosphate and D-xylulose 5-phosphate Escherichia coli
H95N the ratio of turnover number to Km-value is 676fold lower than that of the wild-type enzyme Escherichia coli
H97N site-directed mutants in which the putative metal ion ligand is modified: H95N, H97N, D76N. The mutant enzymes require exogenous metal ions for full activity. Their turnover numbers are greatly reduced whereas the Km-values are only moderately affected. Low levels of aldolase activity are observed with the H97N mutant, but not with D76N or the H95N mutants. The H97N mutant enzyme catalyzes the condensation of dihydroxyacetone and glycolaldehyde phosphate to produce a mixture of L-ribulose 5-phosphate and D-xylulose 5-phosphate Escherichia coli
H97N mutant enzyme with low levels of aldolase activity. The ratio of turnover number to Km-value is 479fold lower than that of the wild-type enzyme Escherichia coli

Inhibitors

Inhibitors Comment Organism Structure
glycoaldehyde phosphate competitive inhibitor of mutant enzyme H97N but not of the wild-type enzyme Escherichia coli
glycolaldehyde
-
Escherichia coli
glycolaldehyde phosphate competitive inhibition of H97N mutant enzyme, no inhibition of wild type enzyme Escherichia coli

KM Value [mM]

KM Value [mM] KM Value Maximum [mM] Substrate Comment Organism Structure
0.06
-
L-ribulose 5-phosphate wild type enzyme, Zn2+ form of enzyme plus 0.1 mM Zn2+ Escherichia coli
0.06
-
L-ribulose 5-phosphate 37°C, pH 7.6, Zn2+-form after dialysis + 0.1 mM Zn2+, wild-type enzyme Escherichia coli
0.087
-
L-ribulose 5-phosphate wild type enzyme, Zn2+ form of enzyme after dialysis Escherichia coli
0.087
-
L-ribulose 5-phosphate 37°C, pH 7.6, Zn2+-form after dialysis, wild-type Escherichia coli
0.096
-
L-ribulose 5-phosphate mutant H95N, Zn2+ form of enzyme plus 0.1 mM Zn2+ Escherichia coli
0.096
-
L-ribulose 5-phosphate 37°C, pH 7.6, Zn2+-form after dialysis + 0.1 mM Zn2+, mutant enzyme H95N Escherichia coli
0.1
-
L-ribulose 5-phosphate L-ribulose 5-phosphate, mutant H97N, Zn2+ form of enzyme after dialysis Escherichia coli
0.1
-
L-ribulose 5-phosphate 37°C, pH 7.6, Zn2+-form after dialysis, mutant enzyme H95N Escherichia coli
0.11
-
L-ribulose 5-phosphate mutant D76N, Zn2+ form of enzyme after dialysis Escherichia coli
0.11
-
L-ribulose 5-phosphate 37°C, pH 7.6, Zn2+-form after dialysis, mutant enzyme D76N Escherichia coli
0.14
-
L-ribulose 5-phosphate L-ribulose 5-phosphate, mutant H97N and D76N, Zn2+ form of enzyme plus 0.1 mM Zn2+ Escherichia coli
0.14
-
L-ribulose 5-phosphate mutant H95N, Zn2+ form of enzyme after dialysis Escherichia coli
0.14
-
L-ribulose 5-phosphate 37°C, pH 7.6, Zn2+-form after dialysis + 0.1 mM Zn2+, mutant enzyme H97N or D76N Escherichia coli
0.14
-
L-ribulose 5-phosphate 37°C, pH 7.6, Zn2+-form after dialysis, mutant enzyme H97N Escherichia coli

Metals/Ions

Metals/Ions Comment Organism Structure
Cu2+ the enzyme preparation contains a mixture of the following metals in order of decreasing abundance: Zn2+, Mn2+, Cu2+ Escherichia coli
Mn2+ the enzyme preparation contains a mixture of the following metals in order of decreasing abundance: Zn2+, Mn2+, Cu2+ Escherichia coli
Zn2+ H95N, H97N, and D76N mutant enzymes require exogenous metal ions for full activity Escherichia coli
Zn2+ the enzyme preparation contains a mixture of the following metals in order of decreasing abundance: Zn2+, Mn2+, Cu2+ Escherichia coli

Molecular Weight [Da]

Molecular Weight [Da] Molecular Weight Maximum [Da] Comment Organism
25522
-
4 * 25522, electrospray mass spectrometry Escherichia coli
127000
-
wild-type enzyme and mutant enzymes H97N, D76N and H95N, gel filtration Escherichia coli

Organism

Organism UniProt Comment Textmining
Escherichia coli
-
-
-
Escherichia coli
-
wild type enzyme and mutants H95N, H97N, and D76N
-

Purification (Commentary)

Purification (Comment) Organism
-
Escherichia coli

Specific Activity [micromol/min/mg]

Specific Activity Minimum [µmol/min/mg] Specific Activity Maximum [µmol/min/mg] Comment Organism
34
-
-
Escherichia coli

Substrates and Products (Substrate)

Substrates Comment Substrates Organism Products Comment (Products) Rev. Reac.
L-Ribulose 5-phosphate
-
Escherichia coli D-Xylulose 5-phosphate
-
?
additional information the mutant enzyme H97N catalyzes the condensation of dihydroxyacetone and glycolaldehyde to produce a mixture of ribulose-5-phosphate and D-xylulose 5-phosphate Escherichia coli ?
-
?

Subunits

Subunits Comment Organism
tetramer 4 * 25522, electrospray mass spectrometry Escherichia coli

Temperature Stability [°C]

Temperature Stability Minimum [°C] Temperature Stability Maximum [°C] Comment Organism
50 55 thermal denaturation themperature of wild-type enzyme and mutant enzymes H97N, D76N and H95N Escherichia coli

Turnover Number [1/s]

Turnover Number Minimum [1/s] Turnover Number Maximum [1/s] Substrate Comment Organism Structure
0.047
-
L-ribulose 5-phosphate mutant H95N, Zn2+ form of enzyme after dialysis Escherichia coli
0.047
-
L-ribulose 5-phosphate 37°C, pH 7.6, Zn2+-form after dialysis, mutant enzyme H95N Escherichia coli
0.048
-
L-ribulose 5-phosphate mutant H97N, Zn2+ form of enzyme after dialysis Escherichia coli
0.048
-
L-ribulose 5-phosphate 37°C, pH 7.6, Zn2+-form after dialysis, mutant enzyme H97N Escherichia coli
0.073
-
L-ribulose 5-phosphate mutant D76N, Zn2+ form of enzyme after dialysis Escherichia coli
0.073
-
L-ribulose 5-phosphate 37°C, pH 7.6, Zn2+-form after dialysis, mutant enzyme D76N Escherichia coli
0.1
-
L-ribulose 5-phosphate mutant H95N, Zn2+ form of enzyme plus 0.1 mM Zn2+ Escherichia coli
0.16
-
L-ribulose 5-phosphate mutant D76N, Zn2+ form of enzyme plus 0.1 mM Zn2+ Escherichia coli
0.16
-
L-ribulose 5-phosphate 37°C, pH 7.6, Zn2+-form after dialysis + 0.1 mM Zn2+, mutant enzyme D76N Escherichia coli
7.3
-
L-ribulose 5-phosphate mutant H97N, Zn2+ form of enzyme plus 0.1 mM Zn2+ Escherichia coli
7.3
-
L-ribulose 5-phosphate 37°C, pH 7.6, Zn2+-form after dialysis + 0.1 mM Zn2+, mutant enzyme H97N Escherichia coli
20.4
-
L-ribulose 5-phosphate wild type enzyme, Zn2+ form of enzyme after dialysis Escherichia coli
20.4
-
L-ribulose 5-phosphate 37°C, pH 7.6, Zn2+-form after dialysis, wild-type Escherichia coli
20.7
-
L-ribulose 5-phosphate wild type enzyme, Zn2+ form of enzyme plus 0.1 mM Zn2+ Escherichia coli
22.4
-
L-ribulose 5-phosphate 37°C, pH 7.6, Zn2+-form after dialysis + 0.1 mM Zn2+, wild-type enzyme Escherichia coli

Ki Value [mM]

Ki Value [mM] Ki Value maximum [mM] Inhibitor Comment Organism Structure
0.37
-
glycolaldehyde 37°C, pH 7.6, mutant enzyme H97N, with L-ribulose 5-phosphate as substrate Escherichia coli