2,3-Butanedione inactivates the [3H]nitrendipine binding sites, whereas diethylpyrocarbonate does not.
The modification of [3H]nitrendipine binding sites in rabbit brain membranes with 2,3-butanedione and diethylpyrocarbonate was investigated. 2,3-Butanedione, an arginine-specific reagent, causes a dose- and time-dependent decrease in the number of [3H]nitrendipine binding sites without altering its dissociation constant. Scatchard analysis of the binding data shows that 50 mM 2,3-butanedione decreases the binding capacity of [3H]nitrendipine from a control value of 71 +/- 6 fmol/mg of protein to 40 +/- 3 fmol/mg of protein. Complete and selective protection against inactivation is provided by nifedipine. No decrease of [3H]nitrendipine binding occurs when membranes are pretreated with selective histidine reagent diethylpyrocarbonate. The results indicate that arginine but not histidine residue in L-type calcium channel domain in critical for [3H]nitrendipine binding.
Costa
B
B
Istituto Policattedra di Discipline Biologiche, Universita di Pisa, Italy.
Giusti
L
L
Martini
C
C
Lucacchini
A
A
D000818:Animals; D001120:Arginine / Q000737:chemistry*; D001665:Binding Sites; D001921:Brain / Q000187:drug effects* / Q000378:metabolism; D015220:Calcium Channels / Q000737:chemistry; D003931:Diacetyl / Q000494:pharmacology*; D004047:Diethyl Pyrocarbonate / Q000494:pharmacology*; D006639:Histidine / Q000737:chemistry*; D008566:Membranes / Q000187:drug effects / Q000378:metabolism; D009568:Nitrendipine / Q000378:metabolism*; D011487:Protein Conformation; D011817:Rabbits; D011869:Radioligand Assay; D014316:Tritium
D015220:Calcium Channels; D014316:Tritium; D006639:Histidine; D001120:Arginine; D009568:Nitrendipine; D003931:Diacetyl; D004047:Diethyl Pyrocarbonate