Specificity of the purified inositol (1,3,4,5) tetrakisphosphate-binding protein from porcine platelets.
The specificity of the inositol 1,3,4,5-tetrakisphosphate binding protein purified from porcine platelets [Cullen et al. (1995) Biochem. J. 305, 139-143] was examined using all the isomers of myo-inositol tetrakisphosphate. From the relative potencies of these compounds it appears that phosphorylation of the 1, 3 and 5 positions is essential for high affinity binding, that there is some tolerance of phosphorylation of the 6-hydroxyl, but none of a phosphate in the 2-position, and that phosphorylation of the 4-hydroxyl has very little influence. The binding of Ins(1,3,4,5)P4 was not appreciably altered by physiological Mg2+ concentrations, and the pH dependence of binding under physiological conditions showed a decline from pH 5.5 to pH 9.0.
School of Biological Sciences, University of East Anglia, Norwich, Norfolk, UK.
P J
PJ
Cullen
S K
SK
Chung
Y T
YT
Chang
A P
AP
Dawson
R F
RF
Irvine
D000818:Animals; D001792:Blood Platelets / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D007295:Inositol Phosphates / Q000378:metabolism*; D008274:Magnesium / Q000494:pharmacology; D011485:Protein Binding; D018160:Receptors, Cytoplasmic and Nuclear / Q000302:isolation & purification / Q000378:metabolism*; D013552:Swine
D007295:Inositol Phosphates; D018160:Receptors, Cytoplasmic and Nuclear; C061107:inositol-1,3,4,5-tetrakisphosphate receptor; C081655:inositol-1,3,4,5-tetrakisphosphate; D008274:Magnesium