The only inositol tetrakisphosphate detectable in avian erythrocytes is the isomer lacking phosphate at position 3: a NMR study.
Avian red blood cells contain a millimolar amount of inositol polyphosphate which plays a role as an allosteric effector of hemoglobin. We confirmed the structure of this substance by NMR techniques as purely myo-inositol 1,3,4,5,6-pentakisphosphate. Based on present knowledge this effector is synthesized from inositol trisphosphate by successive phosphorylation. In a search for biosynthetic and degradative intermediates of inositol pentakisphosphate we found only one inositol tetrakisphosphate isomer. Its structure was unambiguously assigned by proton, 13C- and 31P-NMR to myo-inositol 1,4,5,6-tetrakisphosphate. As in mammalian cells the major inositol tetrakisphosphate isomer is myo-inositol 1,3,4,5-tetrakisphosphate, there seem to be differences between avian red blood cells and mammalian cells in the routes of inositol polyphosphate formation and/or degradation.
D000818:Animals; D004912:Erythrocytes / Q000032:analysis*; D015544:Inositol 1,4,5-Trisphosphate; D007295:Inositol Phosphates / Q000097:blood; D009682:Magnetic Resonance Spectroscopy; D014422:Turkeys / Q000097:blood*
D007295:Inositol Phosphates; C081651:inositol-1,4,5,6-tetrakisphosphate; C013571:inositol pentaphosphate; D015544:Inositol 1,4,5-Trisphosphate