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Literature summary for 2.7.1.39 extracted from

  • Huo, X.; Viola, R.E.
    Substrate specificity and identification of functional groups of homoserine kinase from Escherichia coli (1996), Biochemistry, 35, 16180-16185.
    View publication on PubMed

Protein Variants

Protein Variants Comment Organism
H139L mutant enzyme with diminished kinase activity and ATPase activity 150fold greater than that of the wild-type enzyme Escherichia coli
H202L Km-value for L-homoserine and ATP remain unchanged, the Ki-value for substrate inhibition by L-homoserine increases about 8fold, the turnover-number decreases by 50%,unlike the wild-type enzyme the L-homoserine ethyl, isopropyl, and n-propyl esters show substrate inhibition Escherichia coli
H205Q Km-value for ATP remains unchanged, ATPase activity is within a factor 2 of the wild-type enzyme, the kinase activity is less than 0.03% that of the wild-type enzyme Escherichia coli
R234C no observable homoserine kinase activity, the ATPase activity is nearly 20 times that of the wild-type enzyme at pH 8.0. 7fold increase in Km-value for ATP. Mutant enzyme is sensitive to heat treatment and begins to precipitate at 55°C Escherichia coli
R234H mutant enzyme has a diminished kinase activity, 0.4% of that of the wild-type enzyme, and an enhanced ATPase activity, Km-values for both substrates are unchanged Escherichia coli
R234L Km-value for L-homoserine increases nearly 300fold, the turnover-number decreases by 90fold compared to the wild-type enzyme. Less than a 2fold change in Km for ATP, the inherent ATPase activity increases by 3fold. The mutant enzyme has turnover-numbers for homoserine esters that are only 10% that of homoserine, but has higher affinity for the esters than for L-homoserine itself. L-Cys, a strong inhibitor of the wild-type enzyme, is 50fold less effective as inhibitor of the mutant enzyme. L-Thr no longer inhibits the mutant enzyme. Unlike the wild-type enzyme, addition of 10 mM L-homoserine to the mutant enzyme has no protective effect on the number of arginyl residues titrated with (p-hydroxyphenyl)glyoxal Escherichia coli

Inhibitors

Inhibitors Comment Organism Structure
(4R)-4-hydroxypentan-2-one
-
Escherichia coli
(p-hydroxyphenyl)-glyoxal
-
Escherichia coli
2-amino-3-(phosphonoethyl)thiopropionate
-
Escherichia coli
2-Amino-5-phosphonovalerate
-
Escherichia coli
2-amino-5-phosphovalerate
-
Escherichia coli
L-2-amino-5-hydroxyvalerate substrate inhibition Escherichia coli
L-Cys
-
Escherichia coli
L-Glutamic acid
-
Escherichia coli
L-homoserine
-
Escherichia coli
L-homoserine alpha-methyl ester substrate inhibition Escherichia coli
L-homoserine ethyl ester unlike the wild-type enzyme the mutant enzyme H202L is inhibited Escherichia coli
L-homoserine isopropyl ester unlike the wild-type enzyme the mutant enzyme H202L is inhibited Escherichia coli
L-homoserine n-propyl ester unlike the wild-type enzyme the mutant enzyme H202L is inhibited Escherichia coli
L-norvaline
-
Escherichia coli
L-Thr substrate inhibition Escherichia coli
O-phospho-L-serine
-
Escherichia coli

KM Value [mM]

KM Value [mM] KM Value Maximum [mM] Substrate Comment Organism Structure
0.11
-
ATP mutant enzyme H202L Escherichia coli
0.11
-
L-homoserine mutant enzyme H202L Escherichia coli
0.13
-
ATP wild-type enzyme Escherichia coli
0.13
-
ATP mutant enzyme R234H Escherichia coli
0.13
-
L-homoserine mutant enzyme R234H Escherichia coli
0.14
-
L-homoserine wild-type enzyme Escherichia coli
0.15
-
ATP mutant enzyme H205Q Escherichia coli
0.21
-
ATP mutant enzyme R234L Escherichia coli
0.28
-
L-aspartate beta-semialdehyde wild-type enzyme Escherichia coli
0.49
-
ATP mutant enzyme H139L Escherichia coli
0.88
-
ATP mutant enzyme R234C Escherichia coli
1.1
-
L-2-amino-5-hydroxyvalerate wild-type enzyme Escherichia coli
1.2
-
L-homoserine isopropyl ester wild-type enzyme Escherichia coli
1.9
-
L-homoserine ethyl ester wild-type enzyme Escherichia coli
2.5
-
L-homoserine mutant enzyme H139L Escherichia coli
3.5
-
L-homoserine n-propyl ester wild-type enzyme Escherichia coli
3.7
-
L-homoserine mutant enzyme H205Q Escherichia coli
4.9
-
L-homoserine methyl ester wild-type enzyme Escherichia coli
5.8
-
L-homoserine n-butyl ester wild-type enzyme Escherichia coli
6.2
-
L-homoserine mutant enzyme R234H Escherichia coli
6.9
-
L-homoserine wild-type enzyme Escherichia coli
6.9
-
L-homoserine isobutyl ester wild-type enzyme Escherichia coli
8.5
-
L-homoserine mutant enzyme R234C Escherichia coli
11.6
-
L-2-amino-1,4-butanediol wild-type enzyme Escherichia coli
31.8
-
D-homoserine wild-type enzyme Escherichia coli
40.1
-
L-homoserine mutant enzyme R234L Escherichia coli
58.2
-
L-homoserine mutant enzyme H202L Escherichia coli

Natural Substrates/ Products (Substrates)

Natural Substrates Organism Comment (Nat. Sub.) Natural Products Comment (Nat. Pro.) Rev. Reac.
ATP + L-homoserine Escherichia coli enzyme in the aspartate pathway of amino acid biosynthesis ADP + O-phospho-L-homoserine
-
?

Organism

Organism UniProt Comment Textmining
Escherichia coli
-
-
-

Substrates and Products (Substrate)

Substrates Comment Substrates Organism Products Comment (Products) Rev. Reac.
ATP + D-homoserine 32% of the turnover number with L-homoserine Escherichia coli ADP + O-phospho-D-homoserine
-
?
ATP + L-2-amino-1,4-butanediol 7.9% of the turnover number with L-homoserine Escherichia coli ADP + ?
-
?
ATP + L-2-amino-5-hydroxyvalerate 9.9% of the turnover number with L-homoserine Escherichia coli ADP + L-2-amino-5-phosphovalerate
-
?
ATP + L-aspartate 4-semialdehyde 8.2% of the turnover number with L-homoserine Escherichia coli ?
-
?
ATP + L-homoserine
-
Escherichia coli ADP + O-phospho-L-homoserine
-
?
ATP + L-homoserine enzyme in the aspartate pathway of amino acid biosynthesis Escherichia coli ADP + O-phospho-L-homoserine
-
?
ATP + L-homoserine ethyl ester 74% of the turnover number with L-homoserine Escherichia coli ADP + O-phospho-L-homoserine ethyl ester
-
?
ATP + L-homoserine isopropyl ester 74% of the turnover number with L-homoserine Escherichia coli ADP + O-phospho-L-homoserine isopropyl ester
-
?
ATP + L-homoserine isubutyl ester 84% of the turnover number with L-homoserine Escherichia coli ADP + O-phospho-L-homoserine isobutyl ester
-
?
ATP + L-homoserine methyl ester 80% of the turnover number with L-homoserine Escherichia coli ADP + O-phospho-L-homoserine methyl ester
-
?
ATP + L-homoserine n-butyl ester 160% of the turnover number with L-homoserine Escherichia coli ADP + O-phospho-L-homoserine n-butyl ester
-
?
ATP + L-homoserine n-propyl ester 76% of the turnover number with L-homoserine Escherichia coli ADP + O-phospho-L-homoserine n-propyl ester
-
?
additional information enzyme has inherent ATPase activity Escherichia coli ?
-
?

Turnover Number [1/s]

Turnover Number Minimum [1/s] Turnover Number Maximum [1/s] Substrate Comment Organism Structure
0.007
-
L-homoserine butyl ester mutant R234L Escherichia coli
0.0111
-
L-homoserine propyl ester mutant R234L Escherichia coli
0.018
-
L-homoserine methyl ester mutant R234L Escherichia coli
0.021
-
L-homoserine ethyl ester mutant R234L Escherichia coli
0.2
-
L-homoserine mutant R234L Escherichia coli
2
-
L-2-amino-1,4-butanediol wild-type enzyme Escherichia coli
2.1
-
L-aspartate beta-semialdehyde wild-type enzyme Escherichia coli
2.5
-
L-2-amino-5-hydroxyvalerate wild-type enzyme Escherichia coli
2.5
-
L-homoserine butyl ester mutant H202L Escherichia coli
2.7
-
L-homoserine propyl ester mutant H202L Escherichia coli
3.3
-
D-homoserine wild-type enzyme Escherichia coli
4.1
-
L-homoserine ethyl ester mutant H202L Escherichia coli
5.4
-
L-homoserine methyl ester mutant H202L Escherichia coli
9.1
-
L-homoserine mutant H202L Escherichia coli
13.6
-
L-homoserine ethyl ester wild-type enzyme Escherichia coli
13.6
-
L-homoserine isopropyl ester wild-type enzyme Escherichia coli
14
-
L-homoserine n-propyl ester wild-type enzyme Escherichia coli
14.7
-
L-homoserine methyl ester wild-type enzyme Escherichia coli
16.4
-
L-homoserine isobutyl ester wild-type enzyme Escherichia coli
18.3
-
L-homoserine wild-type enzyme Escherichia coli
29.1
-
L-homoserine n-butyl ester wild-type enzyme Escherichia coli

pH Optimum

pH Optimum Minimum pH Optimum Maximum Comment Organism
8
-
wild-type enzyme Escherichia coli

Ki Value [mM]

Ki Value [mM] Ki Value maximum [mM] Inhibitor Comment Organism Structure
0.2 0.5 L-norvaline wild-type enzyme Escherichia coli
0.2 0.5 L-Glutamic acid wild-type enzyme Escherichia coli
0.2 0.5 (4R)-4-hydroxypentan-2-one wild-type enzyme Escherichia coli
0.3
-
L-Thr wild-type enzyme Escherichia coli
0.3
-
2-amino-3-(phosphonoethyl)thiopropionate wild-type enzyme Escherichia coli
0.46
-
L-Cys wild-type enzyme Escherichia coli
2.7
-
O-phospho-L-serine
-
Escherichia coli
10.4
-
2-amino-5-phosphovalerate
-
Escherichia coli