Cloned (Comment) | Organism |
---|---|
gene TM_0547 , sequence comparisons, recombinant expression of the enzyme in Escherichia coli strain BL21(DE3) | Thermotoga maritima |
Inhibitors | Comment | Organism | Structure |
---|---|---|---|
additional information | L-homoserine oxidation of the Thermotoga maritima enzyme is almost impervious to inhibition by L-threonine, while L-threonine inhibits AK activity in a cooperative manner. The distinctive sequence of the regulatory domain in Thermotoga maritima AK-HseDH is likely responsible for the unique sensitivity to L-threonine. The quaternary structure of this enzyme is not affected by L-threonine | Thermotoga maritima |
KM Value [mM] | KM Value Maximum [mM] | Substrate | Comment | Organism | Structure |
---|---|---|---|---|---|
0.064 | - |
NADP+ | recombinant enzyme, pH 10.5, 55°C | Thermotoga maritima | |
1.81 | - |
L-homoserine | recombinant enzyme, pH 10.5, 55°C | Thermotoga maritima |
Molecular Weight [Da] | Molecular Weight Maximum [Da] | Comment | Organism |
---|---|---|---|
450000 | - |
about, recombinant enzyme, gel filtration | Thermotoga maritima |
Natural Substrates | Organism | Comment (Nat. Sub.) | Natural Products | Comment (Nat. Pro.) | Rev. | Reac. |
---|---|---|---|---|---|---|
L-homoserine + NADP+ | Thermotoga maritima | - |
L-aspartate 4-semialdehyde + NADPH + H+ | - |
? | |
L-homoserine + NADP+ | Thermotoga maritima DSM 3109 | - |
L-aspartate 4-semialdehyde + NADPH + H+ | - |
? | |
L-homoserine + NADP+ | Thermotoga maritima ATCC 43589 | - |
L-aspartate 4-semialdehyde + NADPH + H+ | - |
? | |
L-homoserine + NADP+ | Thermotoga maritima JCM 10099 | - |
L-aspartate 4-semialdehyde + NADPH + H+ | - |
? |
Organism | UniProt | Comment | Textmining |
---|---|---|---|
Thermotoga maritima | Q9WZ17 | - |
- |
Thermotoga maritima ATCC 43589 | Q9WZ17 | - |
- |
Thermotoga maritima DSM 3109 | Q9WZ17 | - |
- |
Thermotoga maritima JCM 10099 | Q9WZ17 | - |
- |
Purification (Comment) | Organism |
---|---|
recombinant enzyme from Escherichia coli strain BL21(DE3) by heat treatment, hydrophobic interaction chromatography, gel filtration, hydroxyapatite chromatography, and ultrafiltration | Thermotoga maritima |
Specific Activity Minimum [µmol/min/mg] | Specific Activity Maximum [µmol/min/mg] | Comment | Organism |
---|---|---|---|
66.5 | - |
purified recombinant enzyme, pH 10.5, 55°C | Thermotoga maritima |
Substrates | Comment Substrates | Organism | Products | Comment (Products) | Rev. | Reac. |
---|---|---|---|---|---|---|
L-homoserine + NADP+ | - |
Thermotoga maritima | L-aspartate 4-semialdehyde + NADPH + H+ | - |
? | |
L-homoserine + NADP+ | - |
Thermotoga maritima DSM 3109 | L-aspartate 4-semialdehyde + NADPH + H+ | - |
? | |
L-homoserine + NADP+ | - |
Thermotoga maritima ATCC 43589 | L-aspartate 4-semialdehyde + NADPH + H+ | - |
? | |
L-homoserine + NADP+ | - |
Thermotoga maritima JCM 10099 | L-aspartate 4-semialdehyde + NADPH + H+ | - |
? | |
additional information | the bifunctional enzyme also exhibits aspartokinase (AK) activity, EC 2.7.2.4. It shows substantial activities of both AK and homoserine dehydrogenase (HseDH) | Thermotoga maritima | ? | - |
- |
|
additional information | the bifunctional enzyme also exhibits aspartokinase (AK) activity, EC 2.7.2.4. It shows substantial activities of both AK and homoserine dehydrogenase (HseDH) | Thermotoga maritima DSM 3109 | ? | - |
- |
|
additional information | the bifunctional enzyme also exhibits aspartokinase (AK) activity, EC 2.7.2.4. It shows substantial activities of both AK and homoserine dehydrogenase (HseDH) | Thermotoga maritima ATCC 43589 | ? | - |
- |
|
additional information | the bifunctional enzyme also exhibits aspartokinase (AK) activity, EC 2.7.2.4. It shows substantial activities of both AK and homoserine dehydrogenase (HseDH) | Thermotoga maritima JCM 10099 | ? | - |
- |
Subunits | Comment | Organism |
---|---|---|
homopentamer or homohexamer | x * 81000, recombinant enzyme, SDS-PAGE, x * 81433, sequence calculation | Thermotoga maritima |
Synonyms | Comment | Organism |
---|---|---|
AK-HseDH | - |
Thermotoga maritima |
bifunctional aspartate kinase-homoserine dehydrogenase | - |
Thermotoga maritima |
HseDH | - |
Thermotoga maritima |
More | see also EC 2.7.2.4 | Thermotoga maritima |
TM_0547 | - |
Thermotoga maritima |
Temperature Optimum [°C] | Temperature Optimum Maximum [°C] | Comment | Organism |
---|---|---|---|
70 | - |
Hse oxidation | Thermotoga maritima |
Temperature Minimum [°C] | Temperature Maximum [°C] | Comment | Organism |
---|---|---|---|
50 | 80 | over 30% of maximal activity within this range, profile overview | Thermotoga maritima |
Temperature Stability Minimum [°C] | Temperature Stability Maximum [°C] | Comment | Organism |
---|---|---|---|
50 | 100 | purified recombinant enzyme, 10 min, completely stable at 50-90°C, loss of 40% activity at 100°C | Thermotoga maritima |
pH Optimum Minimum | pH Optimum Maximum | Comment | Organism |
---|---|---|---|
10.5 | - |
Hse oxidation | Thermotoga maritima |
pH Minimum | pH Maximum | Comment | Organism |
---|---|---|---|
6.5 | 11 | over 60% of maximal activity within this range, profile overview | Thermotoga maritima |
pH Stability | pH Stability Maximum | Comment | Organism |
---|---|---|---|
5 | 12 | purified recombinant enzyme, 10 min, 50°C, completely stable at pH 5.5-10.5, loss of 25% activity at pH 11.0, loss of 70% activity at pH 5.0 and pH 11.5, inactivation at pH 12.0 | Thermotoga maritima |
Cofactor | Comment | Organism | Structure |
---|---|---|---|
NADP+ | - |
Thermotoga maritima | |
NADPH | - |
Thermotoga maritima |
General Information | Comment | Organism |
---|---|---|
evolution | the orientation of the three domains in the bifunctional aspartate kinase-homoserine dehydrogenase (AK-HseDH) homologue found in Thermotoga maritima totally differs from those observed in previously known AK-HseDHs, the domains line up in the order HseDH, AK, and regulatory domain | Thermotoga maritima |
metabolism | biosynthetic pathway from L-aspartate to L-homoserine involving the bifunctional enzyme, overview | Thermotoga maritima |
physiological function | aspartate kinase (AK, EC 2.7.2.4) and homoserine dehydrogenase (HseDH) are involved in the biosynthetic pathway from L-aspartate to L-homoserine (Hse) in plants and microorganisms. Hse is a common precursor for the synthesis of L-methionine, L-threonine, and L-isoleucine. At the first step in this pathway, L-aspartate is phosphorylated to beta-aspartyl phosphate (beta-Ap) by AK | Thermotoga maritima |