Peptides comprising the bulk of rat brain extracts: Isolation, amino acid sequences and biological activity

Chromatographic separation of rat brain extracts followed by automatic Edma n sequencing of the major individual components resulted in identification of 61 endogenous peptides derived from known functional proteins (hemoglobi n, myelin basic protein, cytochrome-e oxidase, etc.) or unknown precursors. The results are compared with the data obtained earlier for bovine brain. Although the sequences of bovine and rat hemoglobin contain about 20% of am ino acid substitutions, the families of structurally related peptides are v ery similar in both extracts. Several other proteins also give rise to iden tical or closely related peptide fragments in the two mammalian species. Th e outlined similarity extends almost exclusively to the most abundant pepti des present in the extracts. The minor components show less overlap. Four h emoglobin-derived peptides isolated from rat brain were shown to be biologi cally active in tumor cells. Eleven are identical to bioactive peptides fro m other species. Ten structurally overlap with bioactive peptides from othe r sources. The data obtained show similar biosynthetic pathways of pool com ponents in different species, the resultant peptides being aimed at fulfill ing related functions. Copyright (C) 2000 European Peptide Society and John Wiley & Sons. Ltd.