Characterization of $[^{3}$H]Guanine Nucleotide Binding Sites in Brain Membranes

Content Provider	Scilit
Author	Childers, Steven R. Snyder, Solomon H.
Copyright Year	1980
Description	Journal: Journal of Neurochemistry [3H]GTP [guanosine triphosphate] and [3H]GMP-PNP [guanosine 5'-(beta, 8-imino)triphosphate, a nonmetabolized analog of GTP] have been utilized as ligands to characterize binding sites of guanine nucleotides to rat brain membranes. Binding of both [3H]GTP and [3H]GMP-PNP is saturable, with respective KD values of 0.76 and 0.42 microM. The number of binding sites for GMP-PNP (4 nmol/g) is three times greater than for GTP (1.5 nmol/g). This discrepancy is caused by rapid degradation of GTP to guanosine by brain membranes, which can be partially prevented by addition of 100 microM-ATP. The binding of [3H]guanine nucleotides is selective, with approximately equipotent inhibition by GTP, GDP, and GMP-PNP (at 0.2--1.0 microM), but no inhibition by other nucleotides at 100 microM concentrations. The bindings sites for guanine nucleotides in brain membranes appear not to be associated with microtubules, since treatments that reduce [3H]colchicine binding by 65% have no effect on [3H]GTP binding. [3H]Guanine nucleotide binding is widely distributed in various organs, with highest levels in liver and brain and lowest levels in skeletal muscle. The characteristics of these binding sites in brain show specificity properties of sites that regulate neurotransmitter receptors and adenylate cyclase.
Related Links	http://onlinelibrary.wiley.com/doi/10.1111/j.1471-4159.1980.tb12505.x/pdf
Ending Page	192
Page Count	10
Starting Page	183
e-ISSN	14714159
DOI	10.1111/j.1471-4159.1980.tb12505.x
Journal	Journal of Neurochemistry
Issue Number	1
Volume Number	35
Language	English
Publisher	Wiley-Blackwell
Publisher Date	1980-07-01
Access Restriction	Open
Subject Keyword	Journal: Journal of Neurochemistry Biochemistry and Molecular Biology Guanine Nucleotide Guanosine Triphosphate
Content Type	Text
Resource Type	Article