Literature summary for 2.7.1.134 extracted from

Whitfield, H.; White, G.; Sprigg, C.; Riley, A.M.; Potter, B.V.L.; Hemmings, A.M.; Brearley, C.A.
An ATP-responsive metabolic cassette comprised of inositol tris/tetrakisphosphate kinase 1 (ITPK1) and inositol pentakisphosphate 2-kinase (IPK1) buffers diphosphosphoinositol phosphate levels (2020), Biochem. J., 477, 2621-2638 .

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Cloned(Commentary)

Cloned (Comment)	Organism
gene ITPK1, sequence comparisons, recombinant expression of C-terminally His-tagged enzyme in Escherichia coli strain Rosetta 2(DE3)pLysS	Arabidopsis thaliana

KM Value [mM]

KM Value [mM]	KM Value Maximum [mM]	Substrate	Comment	Organism	Structure
1.2	-	ATP	pH 7.5, 25°C, recombinant enzyme	Arabidopsis thaliana

Metals/Ions

Metals/Ions	Comment	Organism	Structure
Mg2+	required	Arabidopsis thaliana

Natural Substrates/ Products (Substrates)

Natural Substrates	Organism	Comment (Nat. Sub.)	Natural Products	Comment (Nat. Pro.)	Rev.	Reac.
ATP + 1D-myo-inositol 3,4,5,6-tetrakisphosphate	Arabidopsis thaliana	-	ADP + 1D-myo-inositol 1,3,4,5,6-pentakisphosphate	-	?

Organism

Organism	UniProt	Comment	Textmining
Arabidopsis thaliana	Q9SBA5	-	-

Purification (Commentary)

Purification (Comment)	Organism
recombinant C-terminally His-tagged enzyme from Escherichia coli strain Rosetta 2(DE3)pLysS by nickel affinity chromatography and gel filtration	Arabidopsis thaliana

Substrates and Products (Substrate)

Substrates	Comment Substrates	Organism	Products	Comment (Products)	Rev.	Reac.
ATP + 1D-myo-inositol 1,4,6-trisphosphate	-	Arabidopsis thaliana	ADP + 1D-myo-inositol 1,3,4,6-tetrakisphosphate	-	?
ATP + 1D-myo-inositol 3,4,5,6-tetrakisphosphate	-	Arabidopsis thaliana	ADP + 1D-myo-inositol 1,3,4,5,6-pentakisphosphate	-	?
ATP + 1D-myo-inositol 3,4,5,6-tetrakisphosphate	enzyme ITPK1 has robust enantiospecific hydroxykinase activity against Ins(3,4,5,6)P4	Arabidopsis thaliana	ADP + 1D-myo-inositol 1,3,4,5,6-pentakisphosphate	-	?
ATP + 1D-myo-inositol 3,4,6-trisphosphate	-	Arabidopsis thaliana	ADP + 1D-myo-inositol 1,3,4,6-tetrakisphosphate	-	?
additional information	substrate docking calculations, substrate specificity of Arabidopsis thaliana ITPK1, overview. Lack of Ins(1,4,5,6)P4/Ins(3,4,5,6) P4 product for Ins(1,4,6)P3 or Ins(3,4,6)P3 substrates. Consistent with the phosphorylation of the enantiomeric pair Ins(1,4,5,6)P4/Ins (3,4,5,6)P4, ITPK1 shows phosphorylation of Ins(1,4,6)P3 at the 3-position and Ins(3,4,6)P3 at the 1-position. ITPK1 has robust enantiospecific hydroxykinase activity against Ins(3,4,5,6)P4. With inositol tris/tetrakisphosphate kinase 1 (ITPK1, EC 2.7.1.134) and inositol pentakisphosphate 2-kinase (IPK1, EC 2.7.1.158) combined at a 1:20 ATP:ADP ratio, InsP6 is converted via Ins(1,3,4,5,6)P5 to Ins(3,4,5,6) P4 and/or Ins(1,4,5,6)P4 with concomitant generation of ATP	Arabidopsis thaliana	?	-	-

Synonyms

Synonyms	Comment	Organism
At5g42810	-	Arabidopsis thaliana
inositol tris/tetrakisphosphate kinase 1	-	Arabidopsis thaliana
ITPK1	-	Arabidopsis thaliana

Temperature Optimum [°C]

Temperature Optimum [°C]	Temperature Optimum Maximum [°C]	Comment	Organism
25	-	assay at	Arabidopsis thaliana

pH Optimum

pH Optimum Minimum	pH Optimum Maximum	Comment	Organism
7.5	-	assay at	Arabidopsis thaliana

Cofactor

Cofactor	Comment	Organism	Structure
ATP	-	Arabidopsis thaliana

General Information

General Information	Comment	Organism
evolution	Arabidopsis thaliana ITPK1, belongs to a class of enzyme that has been shown to possess 1-, 5- and 6-hydroxykinase and (InsP6) 5-phosphokinase activities	Arabidopsis thaliana
metabolism	inositol tris/tetrakisphosphate kinase 1 (ITPK1, EC 2.7.1.134) and inositol pentakisphosphate 2-kinase (IPK1, EC 2.7.1.158) comprise a reversible metabolic cassette converting Ins(3,4,5,6)P4 into 5-InsP7 and back in a nucleotide-dependent manner. Ability of Arabidopsis inositol tris/tetrakisphosphate kinase 1 to discriminate between symmetric and enantiomeric substrates in the production of diverse symmetric and asymmetric myo-inositol phosphate and diphospho-myo-inositol phosphate (inositol pyrophosphate) products	Arabidopsis thaliana
additional information	substrate/product analysis using anion exchange chromatography on an acid- and hydroxide-stable quaternary amine functionalized latex, substrate docking calculations, resolvement and measurement of diphosphoinositol phosphates beside lower inositol phosphates without the use of radiolabel, method, overview. Modeling of the binding of the enantiomers Ins(1,4,5,6)P4 and Ins(3,4,5,6)P4 to ITPK1. Significant interaction of the 4-phosphate of Ins(1,4,5,6)P4 and of the 6-phosphate of the Ins(3,4,5,6)P4 in site F. The respective 1- and 3-phosphates of Ins(1,4,5,6)P4 and Ins(3,4,5,6)P4 make contacts in site C. These subsites are likely determinants of the reactivity of ITPK1	Arabidopsis thaliana

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Release 2023.1 (January 2023)