Metabolism of inositol 1,3,4,5-tetrakisphosphate by human erythrocyte membranes. A new mechanism for the formation of inositol 1,4,5-trisphosphate.
Human erythrocyte membranes metabolize inositol 1,3,4,5-tetrakisphosphate [Ins(1,3,4,5)P4] to inositol 1,3,4-trisphosphate [Ins(1,3,4)P3] in the presence of Mg2+. In the absence of Mg2+ a less rapid conversion of Ins(1,3,4,5)P4 into Ins(1,4,5)P3 was revealed. Such an enzyme activity, if present in hormonally sensitive cells, could provide a mechanism for maintaining constant concentrations of Ins(1,4,5)P3 and Ins(1,3,4,5)P4, important for stimulation of Ca2+ entry after Ca2+ mobilization.
Doughney
C
C
Department of Medical Biochemistry, University of Wales College of Medicine, Cardiff, U.K.
McPherson
M A
MA
Dormer
R L
RL
D004910:Erythrocyte Membrane / Q000187:drug effects / Q000378:metabolism*; D006801:Humans; D015544:Inositol 1,4,5-Trisphosphate; D007295:Inositol Phosphates / Q000097:blood*; D008274:Magnesium / Q000494:pharmacology; D013403:Sugar Phosphates / Q000097:blood*
D007295:Inositol Phosphates; D013403:Sugar Phosphates; C081655:inositol-1,3,4,5-tetrakisphosphate; D015544:Inositol 1,4,5-Trisphosphate; D008274:Magnesium