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Literature summary for 1.6.5.10 extracted from

  • Schlegel, B.P.; Ratnam, K.; Penning, T.M.
    Retention of NADPH-linked quinone reductase activity in an aldo-keto reductase following mutation of the catalytic tyrosine (1998), Biochemistry, 37, 11003-11011.
    View publication on PubMed
Search for more literature for 1.6.5.10

Protein Variants

Protein Variants Comment Organism
D50N less than 0.1% of wild-type activity Rattus norvegicus
H117A less than 0.1% of wild-type activity Rattus norvegicus
K84M complete loss of activity Rattus norvegicus
K84R complete loss of activity Rattus norvegicus
Y55F narrow substrate specificity, reduction of selected aromatic quinones and alpha-dicarbonyls. The activation energy for 9,10-phenanthrenequinone reduction is unchanged in Y55 mutants Rattus norvegicus
Y55S narrow substrate specificity, reduction of selected aromatic quinones and alpha-dicarbonyls. The activation energy for 9,10-phenanthrenequinone reduction is unchanged in Y55 mutants Rattus norvegicus

KM Value [mM]

KM Value [mM] KM Value Maximum [mM] Substrate Comment Organism Structure
0.002
-
 9,10-phenanthrenequinone wild-type, pH 6.0, 25°C Rattus norvegicus
0.012
-
 9,10-phenanthrenequinone mutant D50E, pH 6.0, 25°C Rattus norvegicus
0.014
-
 9,10-phenanthrenequinone mutant Y55F, pH 6.0, 25°C Rattus norvegicus
0.026
-
 9,10-phenanthrenequinone mutant Y55S, pH 6.0, 25°C Rattus norvegicus
0.044
-
 9,10-phenanthrenequinone mutant H117A, pH 6.0, 25°C Rattus norvegicus
0.056
-
 9,10-phenanthrenequinone mutant D50N, pH 6.0, 25°C Rattus norvegicus

Organism

Organism UniProt Comment Textmining
Rattus norvegicus P23457
-
-

Renatured (Commentary)

Renatured (Comment) Organism
-
 Rattus norvegicus

Source Tissue

Source Tissue Comment Organism Textmining
liver
-
 Rattus norvegicus
-

Specific Activity [micromol/min/mg]

Specific Activity Minimum [µmol/min/mg] Specific Activity Maximum [µmol/min/mg] Comment Organism
0.000003
-
 substrate (R,S)-camphorquinone, mutant Y55F, pH 6.0, 25°C Rattus norvegicus
0.00002
-
 substrate (R,S)-camphorquinone, mutant Y55S, pH 6.0, 25°C Rattus norvegicus
0.0006
-
 substrate acenaphthenequinone, mutant Y55F, pH 6.0, 25°C Rattus norvegicus
0.0006
-
 substrate acenaphthenequinone, mutant Y55S, pH 6.0, 25°C Rattus norvegicus
0.0016
-
 substrate 9,10-phenanthrenenquinone, mutant Y55S, pH 6.0, 25°C Rattus norvegicus
0.0018
-
 substrate 9,10-phenanthrenenquinone, mutant Y55F, pH 6.0, 25°C Rattus norvegicus
0.0025
-
 substrate (R,S)-camphorquinone, wild-type, pH 6.0, 25°C Rattus norvegicus
0.0038
-
 substrate acenaphthenequinone, wild-type, pH 6.0, 25°C Rattus norvegicus
0.0044
-
 substrate 9,10-phenanthrenenquinone, wild-type, pH 6.0, 25°C Rattus norvegicus

Substrates and Products (Substrate)

Substrates Comment Substrates Organism Products Comment (Products) Rev. Reac.
(R,S)-camphorquinone + NADPH + H+
-
 Rattus norvegicus (R,S)-camphorquinone + NADP+
-
 ?
9,10-phenanthrenequinone + NADPH + H+
-
 Rattus norvegicus 9,10-phenanthrenequinol + NADP+
-
 ?
acenaphthenequinone + NADPH + H+
-
 Rattus norvegicus acenaphthenequinol + NADP+
-
 ?
additional information enzyme displays bifunctional 3alpha-hydroxysteroid dehydrogenase and NADPH reductase (quinone) activities. Quinone reduction occurs via a mechanism that differs from 3-ketosteroid reduction. In this mechanism, the electron donor NADPH and acceptor o-quinone are bound in close proximity, which permits hydride transfer without formal protonation of the acceptor carbonyl by Tyr 55 Rattus norvegicus ?
-
 ?

Synonyms

Synonyms Comment Organism
AKR1C9
-
 Rattus norvegicus
More bifunctional 3alpha-hydroxysteroid dehydrogenase and NADPH reductase (quinone) Rattus norvegicus

Turnover Number [1/s]

Turnover Number Minimum [1/s] Turnover Number Maximum [1/s] Substrate Comment Organism Structure
0.01
-
 9,10-phenanthrenequinone mutant D50N, pH 6.0, 25°C Rattus norvegicus
0.02
-
 9,10-phenanthrenequinone mutant D50E, pH 6.0, 25°C Rattus norvegicus
0.04
-
 9,10-phenanthrenequinone mutant H117A, pH 6.0, 25°C Rattus norvegicus
1.45
-
 9,10-phenanthrenequinone mutant Y55F, pH 6.0, 25°C Rattus norvegicus
1.45
-
 9,10-phenanthrenequinone mutant Y55S, pH 6.0, 25°C Rattus norvegicus
2.85
-
 9,10-phenanthrenequinone wild-type, pH 6.0, 25°C Rattus norvegicus

pH Optimum

pH Optimum Minimum pH Optimum Maximum Comment Organism
additional information
-
 the pH dependency of 9,10-phenanthrenequinone reduction catalyzed by the wild-type enzyme is different to that observed for 3-ketosteroid reduction. The kcat value for 9,10-phenanthrenequinone reduction is pH-dependent with the maximal rate decreasing with increasing pH but reveals an ionizable group with a pKb of 8.90 that must be protonated for maximal activity Rattus norvegicus

Cofactor

Cofactor Comment Organism Structure
NADPH
-
 Rattus norvegicus

kcat/KM [mM/s]

kcat/KM Value [1/mMs-1] kcat/KM Value Maximum [1/mMs-1] Substrate Comment Organism Structure
0.06
-
 9,10-phenanthrenequinone mutant Y55S, pH 6.0, 25°C Rattus norvegicus
0.1
-
 9,10-phenanthrenequinone mutant Y55F, pH 6.0, 25°C Rattus norvegicus
1.43
-
 9,10-phenanthrenequinone wild-type, pH 6.0, 25°C Rattus norvegicus