Purified inositol hexakisphosphate kinase is an ATP synthase: Diphosphoinositol pentakisphosphate as a high-energy phosphate donor

Susan M. Voglmaier, Michael E. Bembenek, Adam I. Kaplin, György Dormán, John D. Olszewski, Glenn D. Prestwich, Solomon H. Snyder

Research output: Contribution to journalArticlepeer-review

Abstract

Diphosphoinositol pentakisphosphate (PP-IP5) and bis(diphospho)inositol tetrakisphosphate (bis-PP-IP4) are recently identified inositol phosphates that possess pyrophosphate bonds. We have purified an inositol hexakisphosphate (IP6) kinase from rat brain supernatants. The pure protein, a monomer of 54 kDa, displays high affinity (K(m) = 0.7 μM) and selectivity for inositol hexakisphosphate as substrate. It can be dissociated from bis(diphospho)inositol tetrakisphosphate synthetic activity. The purified enzyme transfers a phosphate from PP-IP5 to ADP to form ATP. This ATP synthase activity indicates the high phosphate group transfer potential of PP-IP5 and may represent a physiological role for PP-IP5.

Original languageEnglish (US)
Pages (from-to)4305-4310
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Volume93
Issue number9
DOIs
StatePublished - Apr 30 1996

Keywords

  • phosphotransferase
  • pyrophosphate

ASJC Scopus subject areas

  • General

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