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Characterization of two synaptosomal peptides in calf brain
Acta Chemica Scandinavica. Series B: Organic Chemistry and Biochemistry
|January 1, 1980
Summary
Researchers identified two novel low-molecular weight peptides in calf brain nerve terminals. These peptides are released from synaptic vesicles upon stimulation, indicating their role in neuronal signaling.
Area of Science:
- Neuroscience
- Biochemistry
- Molecular Biology
Background:
- Nerve terminals and synaptic vesicles are crucial for neurotransmission.
- Understanding the molecular composition of synaptic vesicles can elucidate neuronal signaling mechanisms.
Purpose of the Study:
- To purify and characterize low-molecular weight peptides from calf brain nerve terminals.
- To investigate the release mechanism and subcellular localization of these peptides.
Main Methods:
- Purification using ion-exchange chromatography, thin-layer chromatography, copper-Sephadex adsorption chromatography, and gel filtration.
- Amino acid sequencing via the dansyl chloride method, carboxypeptidase, and aminopeptidase.
- Stimulation of isolated nerve terminals and vesicles with K+ and Ca2+.
Main Results:
- Two low-molecular weight peptides were successfully purified.
- Tentative sequences obtained: NH2-alanyl-glycyl-glutamyl-phosphoserine-COOH and N-acetylaspartyl-glutamyl-taurine-SO3.
- Peptide release was induced by depolarizing agents (K+, Ca2+) and electrical stimulation, exclusively from synaptic vesicles, not synaptosomes.
Conclusions:
- The identified peptides originate from synaptic vesicles.
- Their release mechanism suggests a role in synaptic function and neurotransmission.