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Literature summary for 4.1.99.2 extracted from

  • Chen, H.Y.; Demidkina, T.V.; Phillips, R.S.
    Site-directed mutagenesis of tyrosine-71 to phenylalanine in Citrobacter freundii tyrosine phenol-lyase: evidence for dual roles of tyrosine-71 as a general acid catalyst in the reaction mechanism and in cofactor binding (1995), Biochemistry, 34, 12276-12283.
    View publication on PubMed
Search for more literature for 4.1.99.2

Protein Variants

Protein Variants Comment Organism
Y71F no activity for beta-elimination of L-Tyr. Can react with S-alkylcysteines, but these substrates exhibit a 1000-10000fold reduced turnover number compared to wild-type. For substrates with good leaving groups S-(o-nitrophenyl)-L-Cys, 3-chloro-L-Ala and O-benzoyl-L-Ser the mutant enzyme exhibits turnover numbers 1.85-7% those of the wild-type enzyme. Tyr 71 plays a dual role, both in cofactor binding in the absence of substrate and also as a general acid catalyst in the elimination of leaving groups from quinoid intermediates Citrobacter freundii

KM Value [mM]

KM Value [mM] KM Value Maximum [mM] Substrate Comment Organism Structure
0.05
-
 S-benzyl-L-Cys mutant enzyme Y71F Citrobacter freundii
0.1
-
 S-(o-nitrophenyl)-L-Cys wild-type enzyme Citrobacter freundii
0.16
-
 S-(o-nitrophenyl)-L-Cys mutant enzyme Y71F Citrobacter freundii
0.2
-
 L-Tyr wild-type enzyme Citrobacter freundii
0.2
-
 S-benzyl-L-Cys wild-type enzyme Citrobacter freundii
0.3
-
 S-ethyl-L-Cys mutant enzyme Y71F Citrobacter freundii
0.52
-
 S-methyl-L-Cys mutant enzyme Y71F Citrobacter freundii
0.8
-
 O-benzoyl-L-Ser mutant enzyme Y71F Citrobacter freundii
2
-
 3-chloro-L-Ala mutant enzyme Y71F Citrobacter freundii
2.9
-
 O-benzoyl-L-Ser mutant enzyme Y71F Citrobacter freundii
3.2
-
 3-chloro-L-Ala mutant enzyme Y71F Citrobacter freundii
3.4
-
 S-methyl-L-Cys wild-type enzyme Citrobacter freundii
6.6
-
 S-ethyl-L-Cys wild-type enzyme Citrobacter freundii

Organism

Organism UniProt Comment Textmining
Citrobacter freundii
-
 wild-type enzyme and mutant enzyme Y71F
-

Substrates and Products (Substrate)

Substrates Comment Substrates Organism Products Comment (Products) Rev. Reac.
3-chloro-L-Ala + H2O
-
 Citrobacter freundii ?
-
 ?
O-benzoyl-L-Ser + H2O
-
 Citrobacter freundii ?
-
 ?
S-(o-nitrophenyl)-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
-
 ?
Tyr + H2O L-Tyr Citrobacter freundii phenol + pyruvate + NH3
-
 ?

Turnover Number [1/s]

Turnover Number Minimum [1/s] Turnover Number Maximum [1/s] Substrate Comment Organism Structure
0.000217
-
 S-ethyl-L-Cys mutant enzyme Y71F Citrobacter freundii
0.000383
-
 S-methyl-L-Cys mutant enzyme Y71F Citrobacter freundii
0.0012
-
 S-benzyl-L-Cys mutant enzyme Y71F Citrobacter freundii
0.053
-
 3-chloro-L-Ala mutant enzyme Y71F Citrobacter freundii
0.15
-
 O-benzoyl-L-Ser mutant enzyme Y71F Citrobacter freundii
0.25
-
 S-(o-nitrophenyl)-L-Cys mutant enzyme Y71F Citrobacter freundii
0.7
-
 3-chloro-L-Ala wild-type enzyme Citrobacter freundii
0.9
-
 S-methyl-L-Cys wild-type enzyme Citrobacter freundii
3.5
-
 L-Tyr wild-type enzyme Citrobacter freundii
8.3
-
 O-benzoyl-L-Ser wild-type enzyme Citrobacter freundii