Cloned (Comment) | Organism |
---|---|
expressed in Escherichia coli BL21(DE3) Codon plus-RIPL cells | Thermotoga maritima |
gene TM_0547 , sequence comparisons, recombinant expression of the enzyme in Escherichia coli strain BL21(DE3) | Thermotoga maritima |
Inhibitors | Comment | Organism | Structure |
---|---|---|---|
L-threonine | inhibits AK activity in a cooperative manner by 90% at 0.35 mM. 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 | |
additional information | L-homoserine oxidation of the Thermotoga maritima enzyme is almost impervious to inhibition by L-threonine | Thermotoga maritima |
KM Value [mM] | KM Value Maximum [mM] | Substrate | Comment | Organism | Structure |
---|---|---|---|---|---|
3.54 | - |
ATP | at pH 7.0 and 55°C | Thermotoga maritima | |
3.54 | - |
ATP | recombinant enzyme, pH 7.5, 55°C | Thermotoga maritima | |
4.66 | - |
L-aspartate | at pH 7.0 and 55°C | Thermotoga maritima | |
4.66 | - |
L-aspartate | recombinant enzyme, pH 7.5, 55°C | Thermotoga maritima |
Metals/Ions | Comment | Organism | Structure |
---|---|---|---|
Mg2+ | 4 mM used in assay conditions | Thermotoga maritima |
Molecular Weight [Da] | Molecular Weight Maximum [Da] | Comment | Organism |
---|---|---|---|
450000 | - |
gel filtration | Thermotoga maritima |
450000 | - |
about, recombinant enzyme, gel filtration | Thermotoga maritima |
Natural Substrates | Organism | Comment (Nat. Sub.) | Natural Products | Comment (Nat. Pro.) | Rev. | Reac. |
---|---|---|---|---|---|---|
ATP + L-aspartate | Thermotoga maritima | - |
ADP + 4-phospho-L-aspartate | - |
? | |
ATP + L-aspartate | Thermotoga maritima DSM 3109 | - |
ADP + 4-phospho-L-aspartate | - |
? | |
ATP + L-aspartate | Thermotoga maritima ATCC 43589 | - |
ADP + 4-phospho-L-aspartate | - |
? | |
ATP + L-aspartate | Thermotoga maritima JCM 10099 | - |
ADP + 4-phospho-L-aspartate | - |
? |
Organism | UniProt | Comment | Textmining |
---|---|---|---|
Thermotoga maritima | - |
- |
- |
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 |
Toyopearl ether-650M column chromatography, Superdex 200 gel filtration and Cellulofine HAP hydroxyl apatite column chromatography | Thermotoga maritima |
Specific Activity Minimum [µmol/min/mg] | Specific Activity Maximum [µmol/min/mg] | Comment | Organism |
---|---|---|---|
103 | - |
purified recombinant enzyme, pH 7.5, 55°C | Thermotoga maritima |
Substrates | Comment Substrates | Organism | Products | Comment (Products) | Rev. | Reac. |
---|---|---|---|---|---|---|
ATP + L-aspartate | - |
Thermotoga maritima | ADP + 4-phospho-L-aspartate | - |
? | |
ATP + L-aspartate | - |
Thermotoga maritima DSM 3109 | ADP + 4-phospho-L-aspartate | - |
? | |
ATP + L-aspartate | - |
Thermotoga maritima ATCC 43589 | ADP + 4-phospho-L-aspartate | - |
? | |
ATP + L-aspartate | - |
Thermotoga maritima JCM 10099 | ADP + 4-phospho-L-aspartate | - |
? | |
additional information | the bifunctional enzyme also exhibits L-homoserine dehydrogenase activity, EC 1.1.1.3. It shows substantial activities of both aspartate kinase (AK) and homoserine dehydrogenase (HseDH) | Thermotoga maritima | ? | - |
- |
|
additional information | the bifunctional enzyme also exhibits L-homoserine dehydrogenase activity, EC 1.1.1.3. It shows substantial activities of both aspartate kinase (AK) and homoserine dehydrogenase (HseDH) | Thermotoga maritima DSM 3109 | ? | - |
- |
|
additional information | the bifunctional enzyme also exhibits L-homoserine dehydrogenase activity, EC 1.1.1.3. It shows substantial activities of both aspartate kinase (AK) and homoserine dehydrogenase (HseDH) | Thermotoga maritima ATCC 43589 | ? | - |
- |
|
additional information | the bifunctional enzyme also exhibits L-homoserine dehydrogenase activity, EC 1.1.1.3. It shows substantial activities of both aspartate kinase (AK) and homoserine dehydrogenase (HseDH) | Thermotoga maritima JCM 10099 | ? | - |
- |
Subunits | Comment | Organism |
---|---|---|
homopentamer or homohexamer | 5 or 6 * 81000, SDS-PAGE | Thermotoga maritima |
homopentamer or homohexamer | 5 or 6 * 81433, calculated from amino acid sequence | Thermotoga maritima |
homopentamer or homohexamer | x * 81000, recombinant enzyme, SDS-PAGE, x * 81433, sequence calculation | Thermotoga maritima |
Synonyms | Comment | Organism |
---|---|---|
AK-HseDH | - |
Thermotoga maritima |
AK-HseDH | bifunctional enzyme with aspartate kinase and homoserine dehydrogenase activities | Thermotoga maritima |
bifunctional aspartate kinase-homoserine dehydrogenase | - |
Thermotoga maritima |
HseDH | - |
Thermotoga maritima |
More | see also EC 1.1.1.3 | Thermotoga maritima |
TM_0547 | - |
Thermotoga maritima |
Temperature Optimum [°C] | Temperature Optimum Maximum [°C] | Comment | Organism |
---|---|---|---|
70 | - |
- |
Thermotoga maritima |
70 | - |
L-aspartate phosphorylation | Thermotoga maritima |
Temperature Minimum [°C] | Temperature Maximum [°C] | Comment | Organism |
---|---|---|---|
50 | 85 | over 50% of maximal activity at 50°C, 80% at 85°C, 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 |
50 | 90 | the enzyme remains stable (more than 90% activity) after 10 min incubation between 50 and 90°C and drops to about 50% activity after 10 min at 100°C | Thermotoga maritima |
pH Optimum Minimum | pH Optimum Maximum | Comment | Organism |
---|---|---|---|
7 | 8 | L-aspartate phosphorylation | Thermotoga maritima |
7.5 | - |
- |
Thermotoga maritima |
pH Minimum | pH Maximum | Comment | Organism |
---|---|---|---|
6.5 | 9.5 | 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 |
5.5 | 10.5 | the enzyme loses no activity when incubated at pH values between 5.5 and 10.5 for 10 min at 50°C | Thermotoga maritima |
Cofactor | Comment | Organism | Structure |
---|---|---|---|
NADP+ | - |
Thermotoga maritima | |
NADPH | - |
Thermotoga maritima |
IC50 Value | IC50 Value Maximum | Comment | Organism | Inhibitor | Structure |
---|---|---|---|---|---|
0.037 | - |
pH 7.5, 55°C | Thermotoga maritima | L-threonine |
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) and homoserine dehydrogenase (HseDH, EC 1.1.1.3) 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 |