Heterogenous inositol tetrakisphosphate binding sites in the adrenal cortex.
Bovine adrenal cortical microsomes possess high (Kd = 3.68 +/- 1.02 X 10(-9) M) and lower (Kd = 9.20 +/- 1.71 X 10(-8) M) affinity binding sites for inositol 1,3,4,5-tetrakisphosphate. The binding to these sites is rapid, saturable (reaches equilibrium by 15 min at 0 degrees C), and reversible. Competition studies with other inositol phosphate analogs indicate that the high affinity binding sites are clearly distinct from the inositol 1,4,5-trisphosphate receptors which are, however, responsible for a fraction of the lower affinity binding. The characteristics of the inositol 1,3,4,5-tetrakisphosphate binding sites described are compatible with their possible receptor function.
Enyedi
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Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115.
Williams
G H
GH
D000302:Adrenal Cortex / Q000378:metabolism*; D000818:Animals; D001665:Binding Sites; D001667:Binding, Competitive; D007295:Inositol Phosphates / Q000378:metabolism*; D007536:Isomerism; D007700:Kinetics; D051381:Rats; D013403:Sugar Phosphates / Q000378:metabolism*
D007295:Inositol Phosphates; D013403:Sugar Phosphates; C081655:inositol-1,3,4,5-tetrakisphosphate