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Literature summary for 2.4.2.1 extracted from

  • Maynes, J.T.; Yam, W.S.; Jenuth, J.P.; Yuan, R.G.; Litster, S.A.; Phipps, B.M.; Snyder, F.F.
    Design of an adenosine phosphorylase by active-site modification of murine purine nucleoside phosphorylase: enzyme kinetics and molecular dynamics simulation of Asn-243 and Lys-244 substitutions of purine nucleoside phosphorylase (1999), Biochem. J., 344, 585-592.
No PubMed abstract available
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Protein Variants

Protein Variants Comment Organism
K244Q ration of turnover-numer/Km is 83% of that for wild-type enzyme, no activity with adenosine Mus musculus
N243D substitution results in an 8fold increase in Km-value for inosine and a 100fold decrease in ratio of turnover-number/Km. Catalyzes phosphorolysis of adenosine with a Km-value of 0.045 mM and ratio of turnover-number/Km 8fold that with inosine, wild-type enzyme shows no activity with adenosine Mus musculus
N243D/K244Q 14fold increase in Km-value for inosine and 7fold decrease in the ratio of turnover-number/Km as compared to wild-type enzyme. Phosphorolysis of adenosine with a Km-value of 0.042 mM and a ratio of turnover-number/Km twice that of the single D243D substitution Mus musculus
N243T mutant enzyme shows no activity with adenosine Mus musculus

Inhibitors

Inhibitors Comment Organism Structure
Formycin A
-
 Mus musculus
formycin B
-
 Mus musculus

KM Value [mM]

KM Value [mM] KM Value Maximum [mM] Substrate Comment Organism Structure
0.028
-
 adenosine mutant enzyme N243D/K244Q, pH 6.0 Mus musculus
0.032
-
 Inosine wild-type enzyme, pH 6.0 Mus musculus
0.042
-
 adenosine mutant enzyme N243D/K244Q, pH 7.0 Mus musculus
0.045
-
 adenosine mutant enzyme N243D, pH 6.0 ot pH 7.0 Mus musculus
0.058
-
 Inosine wild-type enzyme, pH 7.0 Mus musculus
0.0823
-
 Inosine mutant enzyme N243D/K244Q, pH 7.0 Mus musculus
0.484
-
 Inosine mutant enzyme N243D, pH 7.0 Mus musculus
0.691
-
 Inosine mutant enzyme N243D, pH 6.0 Mus musculus
0.729
-
 Inosine mutant enzyme N243D/K244Q, pH 6.0 Mus musculus

Organism

Organism UniProt Comment Textmining
Mus musculus
-
-
-

Substrates and Products (Substrate)

Substrates Comment Substrates Organism Products Comment (Products) Rev. Reac.
adenosine + phosphate wild-type enzyme and mutant enzyme K244Q show no activity with adenosine, mutant enzyme N243D and N243D/K244Q are active with adenosine Mus musculus adenine + alpha-D-ribose 1-phosphate
-
 ?
inosine + phosphate
-
 Mus musculus hypoxanthine + alpha-D-ribose 1-phosphate
-
 ?

Temperature Stability [°C]

Temperature Stability Minimum [°C] Temperature Stability Maximum [°C] Comment Organism
37
-
 10 min, pH 5 or 8, wild-type enzyme and mutant enzyme N243S show no detectable loss in activity, mutant enzyme N243D/K244Q shows 5% loss at pH 8 and 11% loss at pH 5 Mus musculus

Turnover Number [1/s]

Turnover Number Minimum [1/s] Turnover Number Maximum [1/s] Substrate Comment Organism Structure
0.282
-
 adenosine mutant enzyme N243D, pH 7.0 Mus musculus
0.386
-
 Inosine mutant enzyme N243D, pH 7.0 Mus musculus
0.579
-
 adenosine mutant enzyme N243D/K244Q, pH 7.0 Mus musculus
0.71
-
 adenosine mutant enzyme N243D, pH 6.0 Mus musculus
1.14
-
 adenosine mutant enzyme N243D/K244Q, pH 6.0 Mus musculus
1.41
-
 adenosine mutant enzyme N243D/K244Q, pH 6.0 Mus musculus
1.76
-
 Inosine mutant enzyme N243D, pH 6.0 Mus musculus
9.1
-
 Inosine mutant enzyme N243D/K244Q, pH 7.0 Mus musculus
36.4
-
 Inosine mutant enzyme N243D/K244Q, pH 6.0 Mus musculus
38.9
-
 Inosine wild-type enzyme, pH 6.0 Mus musculus
47.3
-
 Inosine wild-type enzyme, pH 7.0 Mus musculus

pH Optimum

pH Optimum Minimum pH Optimum Maximum Comment Organism
6
-
 sharp optimum, mutant enzyme N243D and N243D/K244Q Mus musculus
6.5 7.5 wild-type enzyme Mus musculus

Ki Value [mM]

Ki Value [mM] Ki Value maximum [mM] Inhibitor Comment Organism Structure
0.0685
-
 Formycin A mutant enzyme N243D/K244Q, with adenosine as substrate Mus musculus
0.114
-
 Formycin A mutant enzyme N243D/K244Q, with inosine as substrate Mus musculus
0.143
-
 Formycin A mutant enzyme N243D, with adenosine as substrate Mus musculus
0.279
-
 formycin B wild-type enzyme, with inosine as substrate Mus musculus
0.339
-
 formycin B mutant enzyme N243D/K244Q, with inosine as substrate Mus musculus
0.667
-
 Formycin A wild-type enzyme, with inosine as substrate Mus musculus
0.67
-
 formycin B mutant enzyme N243D, with inosine as substrate Mus musculus
0.705
-
 formycin B mutant enzyme N243D/K244Q, with inosine as substrate Mus musculus