Inositol-polyphosphate multikinase

{{short description|Class of enzymes}}

{{Infobox enzyme

| Name = Inositol-polyphosphate multikinase

| EC_number = 2.7.1.151

| CAS_number = 9077-69-4

| GO_code =

| image =

| width =

| caption =

}}

Inositol-polyphosphate multikinase ({{EC number|2.7.1.151}}, IpK2, IP3/IP4 6-/3-kinase, IP3/IP4 dual-specificity 6-/3-kinase, IpmK, ArgRIII, AtIpk2alpha, AtIpk2beta, inositol polyphosphate 6-/3-/5-kinase) is an enzyme with systematic name ATP:1D-myo-inositol-1,4,5-trisphosphate 6-phosphotransferase.{{cite journal | vauthors = Saiardi A, Erdjument-Bromage H, Snowman AM, Tempst P, Snyder SH | title = Synthesis of diphosphoinositol pentakisphosphate by a newly identified family of higher inositol polyphosphate kinases | journal = Current Biology | volume = 9 | issue = 22 | pages = 1323–6 | date = November 1999 | pmid = 10574768 | doi = 10.1016/S0960-9822(00)80055-X | doi-access = free }}{{cite journal | vauthors = Odom AR, Stahlberg A, Wente SR, York JD | title = A role for nuclear inositol 1,4,5-trisphosphate kinase in transcriptional control | journal = Science | volume = 287 | issue = 5460 | pages = 2026–9 | date = March 2000 | pmid = 10720331 | doi = 10.1126/science.287.5460.2026 }}{{cite journal | vauthors = Stevenson-Paulik J, Odom AR, York JD | title = Molecular and biochemical characterization of two plant inositol polyphosphate 6-/3-/5-kinases | journal = The Journal of Biological Chemistry | volume = 277 | issue = 45 | pages = 42711–8 | date = November 2002 | pmid = 12226109 | doi = 10.1074/jbc.M209112200 | doi-access = free }}{{cite journal | vauthors = Verbsky JW, Chang SC, Wilson MP, Mochizuki Y, Majerus PW | title = The pathway for the production of inositol hexakisphosphate in human cells | journal = The Journal of Biological Chemistry | volume = 280 | issue = 3 | pages = 1911–20 | date = January 2005 | pmid = 15531582 | doi = 10.1074/jbc.M411528200 | doi-access = free }} This enzyme catalyses the following chemical reaction

: 2 ATP + 1D-myo-inositol 1,4,5-trisphosphate $\backslash rightleftharpoons$ 2 ADP + 1D-myo-inositol 1,3,4,5,6-pentakisphosphate (overall reaction)

:(1a) ATP + 1D-myo-inositol 1,4,5-trisphosphate $\backslash rightleftharpoons$ ADP + 1D-myo-inositol 1,4,5,6-tetrakisphosphate

:(1b) ATP + 1D-myo-inositol 1,4,5,6-tetrakisphosphate $\backslash rightleftharpoons$ ADP + 1D-myo-inositol 1,3,4,5,6-pentakisphosphate

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.