Proteolytic conversion of oxytocin by brain synaptic membranes: role of aminopeptidases and endopeptidases
| Autor: | Roberto Stancampiano, Antonio Argiolas, Miriam Melis |
|---|---|
| Rok vydání: | 1991 |
| Předmět: |
Male
endocrine system Vasopressin Physiology Vasopressins Molecular Sequence Data Synaptic Membranes Neuropeptide Biology Oxytocin Biochemistry Aminopeptidase Aminopeptidases Divalent Cellular and Molecular Neuroscience chemistry.chemical_compound Endocrinology Amastatin Endopeptidases medicine Animals Protease Inhibitors Amino Acid Sequence Amino Acids Chromatography High Pressure Liquid chemistry.chemical_classification Phosphoramidon Brain Rats Inbred Strains Endopeptidase Peptide Fragments Rats chemistry hormones hormone substitutes and hormone antagonists medicine.drug |
| Zdroj: | Peptides. 12(5) |
| ISSN: | 0196-9781 |
| Popis: | The proteolytic conversion of oxytocin and vasopressin by purified rat brain synaptic membranes was studied at 37 degrees C and physiological pH 7.4. The formed peptide fragments were isolated by high performance liquid chromatography and characterized by amino acid analysis. When oxytocin was incubated with synaptic membranes, either C- or N-terminal fragments were found. The most abundant were [Cyt6]oxytocin(4-9), [Cyt6]oxytocin(3-9), [Cyt6]oxytocin(2-9), oxytocin(1-8) and oxytocin(1-7). In contrast, only C-terminal fragments, [Cyt6-Arg8]vasopressin(4-9), [Cyt6-Arg8]vasopressin(3-9) and [Cyt6-Arg8]vasopressin(2-9), were found by incubating [Arg8]vasopressin. The formation of C-terminal oxytocin and vasopressin fragments was inhibited by the aminopeptidase inhibitors amastatin and bestatin, while the formation of oxytocin(1-7) and (1-8) was inhibited by the divalent cations Hg(2+) and Zn(2+). The formation of oxytocin(1-7) was also partially prevented by the endopeptidase inhibitor phosphoramidon. The formation of both C- and N-terminal fragments was inhibited by o-phenanthroline. The results suggest that, while [Arg8]vasopressin is metabolized only by membrane-bound aminopeptidases, oxytocin is also metabolized by membrane-bound endopeptidases. |
| Databáze: | OpenAIRE |
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