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D‐[ 35 S(U)]Inositol 1,4,5‐trisphosphorothioate, a novel radioligand for the inositol 1,4,5‐trisphosphate receptor Complex binding to rat cerebellar membranes
Author(s) -
Challiss R.A.John,
Smith Susan M.,
Potter Barry V.L.,
Nahorski Stefan R.
Publication year - 1991
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(91)80368-d
Subject(s) - inositol , radioligand , inositol phosphate , receptor , radioligand assay , binding site , inositol trisphosphate receptor , inositol trisphosphate , biochemistry , chemistry , biophysics , biology
D‐[ 35 S(U)] mya ‐inositol 1,4,5‐trisphosphorothioate ([ 35 S]InsPS 3 ), a synthetic, metabolically stable analogue of inositol 1,4,5‐trisphosphate (InsP 3 ) binds with high affinity ( K a 58.6±9.1 nM) to rat cerebellar revealing a high density of specific binding sites ( D max 21.5±2.1 pmol/mg of protein). Comparison with [ 3 H]InsP 3 binding reveals a higher density of sites labelled by [ 35 S]InsPS 3 and complex competition curves for displacement of specific [ 35 S]insPS 3 by InsP 3 . The results suggests that [ 35 S]InsPS 3 labels two sites in rat cerebellar membranes with equal affinity: the InsP 3 receptor and a site that displays low affinity for InsP 3 .