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Literature summary for 4.1.99.2 extracted from

  • Chen, H.; Gollnick, P.; Phillips, R.S.
    Site-directed mutagenesis of His343-->Ala in Citrobacter freundii tyrosine phenol-lyase. Effects on the kinetic mechanism and rate-determining step (1995), Eur. J. Biochem., 229, 540-549.
    View publication on PubMed

Protein Variants

Protein Variants Comment Organism
H343A all substrates for alpha,beta-elimination, except S-ethyl-L-Cys, exhibit lower turnover number values with the mutant enzyme than with the wild-type enzyme. The mutant shows slower rates of deuterium isotope exchange for L-Phe and L-Met than does the wild type enzyme. The turnover-number for 3-fluoro-L-Tyr is pH-dependent for the mutant enzyme, whereas it is pH-independent for the wild-type enzyme. His343 does play an important function in catalysis, possibly by facilitating the conformational change from an ‘open' to ‘closed' form when substrates bind Citrobacter freundii

KM Value [mM]

KM Value [mM] KM Value Maximum [mM] Substrate Comment Organism Structure
0.1
-
S-(o-nitrophenyl)-L-Cys wild-type enzyme Citrobacter freundii
0.1
-
3-fluoro-L-Tyr wild-type enzyme Citrobacter freundii
0.2
-
L-Tyr wild-type enzyme Citrobacter freundii
0.2
-
S-benzyl-L-Cys wild-type enzyme Citrobacter freundii
0.5
-
S-(o-nitrophenyl)-L-Cys mutant enzyme H343A Citrobacter freundii
1.2
-
S-ethyl-L-Cys mutant enzyme H343A Citrobacter freundii
1.2
-
S-benzyl-L-Cys mutant enzyme H343A Citrobacter freundii
1.2
-
3-fluoro-L-Tyr mutant enzyme H343A Citrobacter freundii
2.2
-
L-Tyr mutant enzyme H343A Citrobacter freundii
3.4
-
S-methyl-L-Cys wild-type enzyme Citrobacter freundii
6.6
-
S-ethyl-L-Cys wild-type enzyme Citrobacter freundii
11
-
L-Ala wild-type enzyme Citrobacter freundii
11
-
L-Ser mutant enzyme H343A Citrobacter freundii
12.99
-
S-methyl-L-Cys mutant enzyme H343A Citrobacter freundii
18
-
L-Ser wild-type enzyme Citrobacter freundii
32
-
D-Ala wild-type enzyme, alpha,beta-elimination Citrobacter freundii
56.4
-
S-methyl-L-Cys wild-type enzyme Citrobacter freundii
103
-
L-Ala mutant enzyme H343A Citrobacter freundii

Organism

Organism UniProt Comment Textmining
Citrobacter freundii
-
wild type enzyme and mutant enzyme H343A
-

Purification (Commentary)

Purification (Comment) Organism
mutant enzyme His343Ala Citrobacter freundii

Specific Activity [micromol/min/mg]

Specific Activity Minimum [µmol/min/mg] Specific Activity Maximum [µmol/min/mg] Comment Organism
1.9
-
-
Citrobacter freundii

Substrates and Products (Substrate)

Substrates Comment Substrates Organism Products Comment (Products) Rev. Reac.
Ala + H2O L-Ala Citrobacter freundii ?
-
?
Ala + H2O D-Ala Citrobacter freundii ?
-
?
D-Ala + H2O
-
Citrobacter freundii ?
-
?
S-(o-nitrophenyl)-L-Cys + H2O
-
Citrobacter freundii ?
-
?
S-benzoyl-L-Cys + H2O
-
Citrobacter freundii ?
-
?
S-benzyl-L-Cys + H2O
-
Citrobacter freundii ? + pyruvate + NH3
-
?
S-ethyl-L-Cys + H2O
-
Citrobacter freundii ?
-
?
S-methyl-L-Cys + H2O
-
Citrobacter freundii ? + pyruvate + NH3
-
?
Ser + H2O L-Ser Citrobacter freundii ? + pyruvate + NH3
-
?
Tyr + H2O
-
Citrobacter freundii phenol + pyruvate + NH3
-
?

Turnover Number [1/s]

Turnover Number Minimum [1/s] Turnover Number Maximum [1/s] Substrate Comment Organism Structure
0.004
-
D-Ala mutant enzyme H343A Citrobacter freundii
0.01
-
D-Ala wild-type enzyme Citrobacter freundii
0.02
-
S-benzoyl-L-Cys mutant enzyme H343A Citrobacter freundii
0.03
-
L-Ala wild-type enzyme Citrobacter freundii
0.07
-
L-Ser mutant enzyme H343A Citrobacter freundii
0.15
-
S-methyl-L-Cys mutant enzyme H343A Citrobacter freundii
0.17
-
L-Ser wild-type enzyme Citrobacter freundii
0.18
-
3-fluoro-L-Tyr mutant enzyme H343A Citrobacter freundii
0.42
-
L-Tyr mutant enzyme H343A Citrobacter freundii
0.52
-
S-benzyl-L-Cys wild-type enzyme Citrobacter freundii
1.4
-
3-fluoro-L-Tyr wild-type enzyme Citrobacter freundii
1.4
-
S-ethyl-L-Cys mutant enzyme H343A Citrobacter freundii
1.55
-
S-(o-nitrophenyl)-L-Cys mutant enzyme H343A Citrobacter freundii
3.5
-
L-Tyr wild-type enzyme Citrobacter freundii
3.88
-
S-ethyl-L-Cys wild-type enzyme Citrobacter freundii
5.1
-
S-(o-nitrophenyl)-L-Cys wild-type enzyme Citrobacter freundii