Open AccessRegulation of cyclic GMP binding to retinal rod membranes by calcium
Author(s) -
CARETTA Antonio,
CAVAGGIONI Andrea,
GRIMALDI Roberta,
SORBI Robert T.
Publication year - 1988
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1988.tb14354.x-i2
Subject(s) - allosteric regulation , biophysics , membrane , cyclic gmp , calcium , visual phototransduction , chemistry , binding site , microbiology and biotechnology , retinal , biochemistry , biology , receptor , enzyme , organic chemistry
The apparently cooperative binding of 8‐(5‐thioacetamidofluorescein)‐cGMP (SAF‐cGMP) to cGMP‐binding sites of the rod outer segments is regulated by Ca 2+ in the 0.1‐1 μM activity range. High Ca 2+ reduces, and low Ca 2+ increases the affinity of SAF‐cGMP binding. This regulation involves only intrinsic membrane components. It is proposed that an allosteric regulation of cGMP binding by Ca 2+ can contribute to photoreceptor potential adaptation.