IUBMB Enzyme Nomenclature


Accepted name: inositol-polyphosphate multikinase

Reaction: (1a) ATP + 1D-myo-inositol 1,4,5-trisphosphate = ADP + 1D-myo-inositol 1,4,5,6-tetrakisphosphate
(1b) ATP + 1D-myo-inositol 1,4,5,6-tetrakisphosphate = ADP + 1D-myo-inositol 1,3,4,5,6-pentakisphosphate

For diagram, click here

Other name(s): IpK2; IP3/IP4 6-/3-kinase; IP3/IP4 dual-specificity 6-/3-kinase; IpmK; ArgRIII; AtIpk2α; AtIpk2β; inositol polyphosphate 6-/3-/5-kinase

Systematic name: ATP:1D-myo-inositol-1,4,5-trisphosphate 6-phosphotransferase

Comments: This enzyme also phosphorylates Ins(1,4,5)P3 to Ins(1,3,4,5)P4, Ins(1,3,4,5)P4 to Ins(1,3,4,5,6)P5, and Ins(1,3,4,5,6)P4 to Ins(PP)P4, isomer unknown. The enzyme from the plant Arabidopsis thaliana can also phosphorylate Ins(1,3,4,6)P4 and Ins(1,2,3,4,6)P5 at the D-5-position to produce 1,3,4,5,6-pentakisphosphate and inositol hexakisphosphate (InsP6), respectively [3]. Yeast produce InsP6 from Ins(1,4,5)P3 by the actions of this enzyme and EC, inositol-pentakisphosphate 2-kinase [4].

Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, PDB, CAS registry number: 9077-69-4


1. Saiardi, A., Erdjument-Bromage, H., Snowman, A.M., Tempst, P. and Snyder, S.H. Synthesis of diphosphoinositol pentakisphosphate by a newly identified family of higher inositol polyphosphate kinases. Curr. Biol. 9 (1999) 1323-1326. [PMID: 10574768]

2. Odom, A.R., Stahlberg, A., Wente, S.R. and York, J.D. A role for nuclear inositol 1,4,5-trisphosphate kinase in transcriptional control. Science 287 (2000) 2026-2029. [PMID: 10720331]

3. Stevenson-Paulik, J., Odom, A.R. and York, J.D. Molecular and biochemical characterization of two plant inositol polyphosphate 6-/3-/5-kinases. J. Biol. Chem. 277 (2002) 42711-42718. [PMID: 12226109]

4. Verbsky, J.W., Chang, S.C., Wilson, M.P., Mochizuki, Y. and Majerus, P.W. The pathway for the production of inositol hexakisphosphate in human cells. J. Biol. Chem. 280 (2005) 1911-1920. [PMID: 15531582]

[EC created 2002, modified 2006]

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