The detection, purification, structural characterization, and metabolism of diphosphoinositol pentakisphosphate(s) and bisdiphosphoinositol tetrakisphosphate(s).
A new class of inositol phosphates containing energy-rich pyrophosphoryl residues has been characterized. D/L-1-Diphosphoinositol pentakisphosphate(s) and D/L-bis-(1,4)-diphosphoinositol tetrakisphosphate(s) are present as soluble ionic species in the cytosol of amoebae (Dictyostelium discoideum) at concentrations in the range of 0.05-0.25 mM. These compounds are rapidly metabolized in intact cells and can be synthesized in cell lysates from myo-inositol hexakisphosphate in the presence of ATP. Their phosphomonoester groups have predicted C-O-P bond energies of between 3.3 and 4 kcal mol-1; however, the bond energies of the P-O-P links in their diphosphate moieties are 6.6 kcal mol-1 and hence similar to the equivalent bonds in ADP, indicating a potential role for these compounds as phosphate donors in phosphotransferase reactions. Compounds with similar chromatographic properties are found in a variety of mammalian cell types.
Stephens
L
L
Biochemistry Department, Institute of Animal Physiology and Genetics Research, Babraham, Cambridge, United Kingdom.
Radenberg
T
T
Thiel
U
U
Vogel
G
G
Khoo
K H
KH
Dell
A
A
Jackson
T R
TR
Hawkins
P T
PT
Mayr
G W
GW
D000818:Animals; D002478:Cells, Cultured; D002851:Chromatography, High Pressure Liquid; D004023:Dictyostelium / Q000737:chemistry / Q000378:metabolism; D006801:Humans; D007294:Inositol / Q000737:chemistry; D007295:Inositol Phosphates / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism; D009682:Magnetic Resonance Spectroscopy; D051379:Mice; D015394:Molecular Structure; D010833:Phytic Acid / Q000378:metabolism; D016339:Spectrometry, Mass, Fast Atom Bombardment; D014407:Tumor Cells, Cultured
D007295:Inositol Phosphates; C079849:1-diphosphoinositol pentakisphosphate; C079848:bis(1,4)-diphosphoinositol tetrakisphosphate; D007294:Inositol; D010833:Phytic Acid