Updated BioCyc iOS App now
available in iTunes store
Updated BioCyc iOS App now
available in iTunes store
Updated BioCyc iOS App now
available in iTunes store
Updated BioCyc iOS App now
available in iTunes store
Updated BioCyc iOS App now
available in iTunes store

MetaCyc Reaction:

Superclasses: Reactions Classified By Conversion TypeSimple ReactionsChemical Reactions
Reactions Classified By SubstrateSmall-Molecule Reactions

EC Number:,

Enzymes and Genes:

Homo sapiens: inositol hexakisphosphate kinase 1Inferred from experiment: IP6K1
inositol hexakisphosphate kinase 3Inferred from experiment: IP6K3
inositol hexakisphosphate kinase 2Inferred from experiment: IP6K2

In Pathway: inositol pyrophosphates biosynthesis

Supersedes EC numbers:,

The direction shown, i.e. which substrates are on the left and right sides, is in accordance with the Enzyme Commission system.

Mass balance status: Balanced.

Direct generic reaction:
ATP + a diphospho-1D-myo-inositol pentakisphosphate = ADP + a bis(diphospho)-1D-myo-inositol tetrakisphosphate (2.7.4.-)

Enzyme Commission Primary Name for inositol-hexakisphosphate kinase

Enzyme Commission Synonyms for ATP:1D-myo-inositol-hexakisphosphate phosphotransferase, IP6K

Enzyme Commission Primary Name for diphosphoinositol-pentakisphosphate kinase

Enzyme Commission Synonyms for PP-IP5 kinase, diphosphoinositol pentakisphosphate kinase, ATP:5-diphospho-1D-myo-inositol-pentakisphosphate phosphotransferase, PP-InsP5 kinase, PPIP5K, PPIP5K1, PPIP5K2, VIP1, VIP2

Standard Gibbs Free Energy (ΔrG in kcal/mol): -7.651367Inferred by computational analysis [Latendresse13]

Formerly EC

Enzyme Commission Summary for
This reaction is considered a second official reaction for EC

Three mammalian isoforms are known to exist.

Enzyme Commission Summary for
This enzyme is activated by osmotic shock. D-myo-inositol 1,3,4,5,6-pentakisphosphate, 1D-myo-inositol 1,5-bis(diphosphate) 2,3,4,6-tetrakisphosphate and 1D-myo-inositol bisdiphosphate triphosphate are not substrates [Choi07].

Citations: [Lin09, Saiardi99, Schell99, Albert97, Wang12d, Shears95, Fridy07]

Gene-Reaction Schematic

Gene-Reaction Schematic

Relationship Links: BRENDA:EC:, BRENDA:EC:, ENZYME:EC:, ENZYME:EC:, IUBMB-ExplorEnz:EC:, IUBMB-ExplorEnz:EC:

Created 29-Oct-2009 by Caspi R, SRI International


Albert97: Albert C, Safrany ST, Bembenek ME, Reddy KM, Reddy K, Falck J, Brocker M, Shears SB, Mayr GW (1997). "Biological variability in the structures of diphosphoinositol polyphosphates in Dictyostelium discoideum and mammalian cells." Biochem J 327 ( Pt 2);553-60. PMID: 9359429

Choi07: Choi JH, Williams J, Cho J, Falck JR, Shears SB (2007). "Purification, sequencing, and molecular identification of a mammalian PP-InsP5 kinase that is activated when cells are exposed to hyperosmotic stress." J Biol Chem 282(42);30763-75. PMID: 17702752

Fridy07: Fridy PC, Otto JC, Dollins DE, York JD (2007). "Cloning and characterization of two human VIP1-like inositol hexakisphosphate and diphosphoinositol pentakisphosphate kinases." J Biol Chem 282(42);30754-62. PMID: 17690096

Latendresse13: Latendresse M. (2013). "Computing Gibbs Free Energy of Compounds and Reactions in MetaCyc."

Lin09: Lin H, Fridy PC, Ribeiro AA, Choi JH, Barma DK, Vogel G, Falck JR, Shears SB, York JD, Mayr GW (2009). "Structural analysis and detection of biological inositol pyrophosphates reveal that the family of VIP/diphosphoinositol pentakisphosphate kinases are 1/3-kinases." J Biol Chem 284(3);1863-72. PMID: 18981179

Saiardi99: Saiardi A, Erdjument-Bromage H, Snowman AM, Tempst P, Snyder SH (1999). "Synthesis of diphosphoinositol pentakisphosphate by a newly identified family of higher inositol polyphosphate kinases." Curr Biol 9(22);1323-6. PMID: 10574768

Schell99: Schell MJ, Letcher AJ, Brearley CA, Biber J, Murer H, Irvine RF (1999). "PiUS (Pi uptake stimulator) is an inositol hexakisphosphate kinase." FEBS Lett 461(3);169-72. PMID: 10567691

Shears95: Shears SB, Ali N, Craxton A, Bembenek ME (1995). "Synthesis and metabolism of bis-diphosphoinositol tetrakisphosphate in vitro and in vivo." J Biol Chem 270(18);10489-97. PMID: 7737983

Wang12d: Wang H, Falck JR, Hall TM, Shears SB (2012). "Structural basis for an inositol pyrophosphate kinase surmounting phosphate crowding." Nat Chem Biol 8(1);111-6. PMID: 22119861

Report Errors or Provide Feedback
Please cite the following article in publications resulting from the use of MetaCyc: Caspi et al, Nucleic Acids Research 42:D459-D471 2014
Page generated by Pathway Tools version 19.5 (software by SRI International) on Fri Apr 29, 2016, biocyc13.