Cloned (Comment) | Organism |
---|---|
gene ipk2, analysis of genes coexpressing with AtIPK, At1g26640, overview. Overexpression of gene ipk1 in transgenic tobacco plants | Arabidopsis thaliana |
Protein Variants | Comment | Organism |
---|---|---|
additional information | generation of two Arabidopsis T-DNA insertion lines (ipk1, ipk2) by reverse genetics. Quantitative RT-PCR (qRT-PCR) expression analysis with two sets of gene-specific primers, one located upstream of T-DNA insertions and the other downstream near the 3' end of the gene. No AtIPK transcripts are detected in ipk1, whereas transcript levels are reduced by 83% in ipk2, with remaining expression likely a result of residual splicing despite the intron-localized T-DNA insertion. Both ipk1 and ipk2 seedlings show a significant decrease in campesterol and sitosterol content (50% and 37% of wild-type, respectively), while the stigmasterol levels are unchanged | Arabidopsis thaliana |
KM Value [mM] | KM Value Maximum [mM] | Substrate | Comment | Organism | Structure |
---|---|---|---|---|---|
0.032 | - |
isopentenyl phosphate | pH and temperature not specified in the publication | Arabidopsis thaliana | |
0.033 | - |
dimethylallyl phosphate | pH and temperature not specified in the publication | Arabidopsis thaliana | |
0.22 | - |
geranyl phosphate | pH and temperature not specified in the publication | Arabidopsis thaliana |
Localization | Comment | Organism | GeneOntology No. | Textmining |
---|---|---|---|---|
cytosol | - |
Arabidopsis thaliana | 5829 | - |
additional information | not in chloroplasts | Arabidopsis thaliana | - |
- |
Metals/Ions | Comment | Organism | Structure |
---|---|---|---|
Mg2+ | required | Arabidopsis thaliana |
Natural Substrates | Organism | Comment (Nat. Sub.) | Natural Products | Comment (Nat. Pro.) | Rev. | Reac. |
---|---|---|---|---|---|---|
ATP + dimethylallyl phosphate | Arabidopsis thaliana | - |
ADP + dimethylallyl diphosphate | - |
? | |
ATP + geranyl phosphate | Arabidopsis thaliana | low activity | ADP + geranyl diphosphate | - |
? | |
ATP + isopentenyl phosphate | Arabidopsis thaliana | - |
ADP + isopentenyl diphosphate | - |
? |
Organism | UniProt | Comment | Textmining |
---|---|---|---|
Arabidopsis thaliana | Q8H1F7 | IPK2; gene IPK2 | - |
Source Tissue | Comment | Organism | Textmining |
---|---|---|---|
leaf | - |
Arabidopsis thaliana | - |
Substrates | Comment Substrates | Organism | Products | Comment (Products) | Rev. | Reac. |
---|---|---|---|---|---|---|
ATP + dimethylallyl phosphate | - |
Arabidopsis thaliana | ADP + dimethylallyl diphosphate | - |
? | |
ATP + geranyl phosphate | low activity | Arabidopsis thaliana | ADP + geranyl diphosphate | - |
? | |
ATP + isopentenyl phosphate | - |
Arabidopsis thaliana | ADP + isopentenyl diphosphate | - |
? |
Synonyms | Comment | Organism |
---|---|---|
Ipk2 | - |
Arabidopsis thaliana |
isopentenyl phosphate kinase | - |
Arabidopsis thaliana |
Turnover Number Minimum [1/s] | Turnover Number Maximum [1/s] | Substrate | Comment | Organism | Structure |
---|---|---|---|---|---|
0.0039 | - |
geranyl phosphate | pH and temperature not specified in the publication | Arabidopsis thaliana | |
2.7 | - |
dimethylallyl phosphate | pH and temperature not specified in the publication | Arabidopsis thaliana | |
3.7 | - |
isopentenyl phosphate | pH and temperature not specified in the publication | Arabidopsis thaliana |
Cofactor | Comment | Organism | Structure |
---|---|---|---|
ATP | - |
Arabidopsis thaliana |
General Information | Comment | Organism |
---|---|---|
malfunction | AtIPK knockout or knockdown affects formation of two of the three predominant Arabidopsis sterols. Similar sterol levels in knockout (ipk1) and knockdown (ipk2) mutants indicate that remaining AtIPK expression in ipk2 supports only marginal flux toward IPP/DMAPP formation without increasing downstream terpenoid production relative to the null ipk knockout. The lack of reduction in stigmasterol levels suggests that the reduced pool of sitosterol, the immediate precursor of stigmasterol, is still sufficient to sustain unaltered production of the latter. In addition, emission of beta-caryophyllene, the most abundant sesquiterpene compound in Arabidopsis is reduced by 25-31% in flowers of ipk mutants compared with wild-type | Arabidopsis thaliana |
metabolism | the enzyme is involved in the isopentenyl phosphate kinase pathway. The absence of two components of the mevalonate (MVA) pathway from archaeal genomes leads to the discovery of an alternative mevalonate pathway with isopentenyl phosphate kinase (IPK) catalyzing the final step, the formation of isopentenyl diphosphate. Despite the fact that plants contain the complete classical mevalonate pathway, IPK homologues are identified in every sequenced green plant genome. Position and potential role of IPK in the plant terpenoid metabolic network, overview | Arabidopsis thaliana |
physiological function | IPK may be functionally connected to the mevalonate (MVA) pathway and biosynthesis of downstream terpenoids, including sesquiterpenes, triterpenes, and sterols. Enzyme IPK catalyzes the final step in the formation of isopentanyl diphosphate. Plants IPK plays a role in modulating the formation and pool sizes of farnesyl diphosphate-derived terpenoids. IPK also contributes to formation of geranyl diphosphate-derived terpenoids in plastids | Arabidopsis thaliana |
kcat/KM Value [1/mMs-1] | kcat/KM Value Maximum [1/mMs-1] | Substrate | Comment | Organism | Structure |
---|---|---|---|---|---|
0.018 | - |
geranyl phosphate | pH and temperature not specified in the publication | Arabidopsis thaliana | |
85 | - |
dimethylallyl phosphate | pH and temperature not specified in the publication | Arabidopsis thaliana | |
101 | - |
isopentenyl phosphate | pH and temperature not specified in the publication | Arabidopsis thaliana |