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A putative opioid-peptide processing activity in enriched Golgi fraction from rat brain
Biochemical and Biophysical Research Communications
|July 16, 1986
Summary
Researchers found a novel enzyme in rat brain Golgi membranes that processes opioid peptides like Dynorphin 1-13. This enzyme may play a role in proenkephalin processing within the cell.
Area of Science:
- Neuroscience
- Biochemistry
- Cell Biology
Background:
- Opioid peptides are crucial for pain modulation and reward pathways.
- Processing of proenkephalin into active opioid peptides involves specific enzymatic cleavage.
Purpose of the Study:
- To identify and characterize novel enzymatic activities involved in opioid peptide processing within the rat brain Golgi apparatus.
Main Methods:
- Preparation of a Golgi-enriched fraction from rat brain.
- Assay of enzyme activity using opioid peptide substrates (Dynorphin 1-13, alpha- and beta-Neoendorphin).
- Determination of pH optimum and inhibition by protease inhibitors.
Main Results:
- A novel endopeptidase activity was identified in Golgi membranes, distinct from known contaminants.
- The enzyme cleaves Dynorphin 1-13, alpha- and beta-Neoendorphin at paired basic residues, releasing Leucine-enkephalin-Arg6.
- The activity exhibits a pH optimum around 9 and is sensitive to serine-protease inhibitors.
Conclusions:
- The identified endopeptidase is localized to the Golgi apparatus.
- Its substrate specificity and characteristics suggest a role in the post-translational processing of proenkephalin.