Mass spectrometric studies of some synaptosomal and synthetic peptides

Mass spectra were recorded using direct inlet and electron impact ionization from two synthetic peptides, N-acetyl-aspartyl-4-aminobutyric acid and gamma-glutamyl-taurine and a natural peptide, N-acetyl-aspartyl-glycyl-alanyl-aspartyl-serine, isolated from calf brain synaptosomes. The peptides were studied either underivatized or first acetylated with acetic acid anhydride and then permethylated with methyl iodide. The synthetic peptides were used to check the completeness of the derivatization reactions.