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Effect of Depolarizing Agents on the Incorporation of Amino Acids into Soluble Cytoplasmic and Membrane‐Bound Proteins of Synaptosome Fractions
Author(s) -
Boyar M. M.,
CoutinhoNetto J.,
AbdulGhani A. S.,
Bradford H. F.
Publication year - 1981
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.1981.tb06304.x
Subject(s) - depolarization , trichloroacetic acid , synaptosome , hydrolysate , leucine , amino acid , chemistry , biochemistry , membrane protein , membrane , membrane potential , biophysics , biology , hydrolysis
The incorporation of [U‐ 14 C] protein hydrolysate and [U‐ 14 C]leucine into the trichloroacetic acid (TCA)‐insoluble membrane and the soluble synaptoplasm proteins of synaptosomes was studied. Following treatment with the depolarizing agents veratrine, Tityus toxin, or potassium, the specific radioactivity of both precursor pool and proteins was measured to examine the link between protein labeling and the fall in the free amino acid pool due to depolarization‐induced release of glutamate and aspartate. By reducing the size of the fall in precursor pool due to depolarization by using a nontransmitter amino acid such as leucine (as compared with the usual use of protein hydrolysate), it was shown that the amount by which the pool is reduced is proportional to the change in the protein labeling observed. These results confirm that membrane depolarization causes a large increase in the labeling of membrane‐bound proteins as compared with the soluble synaptosomal proteins.