Orensanz LM, Ambrosio E, Fernández I, Montero MT. A re-examination of the Na+-independent binding of [3H]beta-alanine to rat brain stem-spinal cord.
Neurochem Res 1988;
13:1133-8. [PMID:
3148869 DOI:
10.1007/bf00971630]
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Abstract
The Na+-independent binding of [3H]beta-alanine to rat brain stem plus spinal cord was reinvestigated, in order to study in more detail the characteristics of previously described beta-alanine binding processes. Binding was absent when amino acid-free postnuclear supernatants or crude synaptic membranes were used. Experiments performed with several other Na+-free preparations showed a sole binding component, irrespective of the preparation used. Biochemical characterization of this Na+-independent binding, using frozen/thawed/washed synaptosomal-mitochondrial fractions, showed that binding reached a plateau between 7 min and 13 min, increasing thereafter. Binding was linear with fraction protein over a range of 200-415 micrograms/ml incubation medium. Binding was completely inhibited by glycine, alanine, alpha-aminobutyric acid, beta-aminoisobutyric acid, hypotaurine and strychnine, and to a lesser extent by 2,2-dimethyl-beta-alanine, brucine and gelsemine. It was insensitive to taurine, gamma-aminobutyric acid (GABA), 2-guanidinoethanesulfonic acid (GES), carnosine, and bicuculline methiodide. Binding was reversible, saturable (KD 20 microM), and heat sensitive.
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