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Specificity of the dynorphin-processing endoprotease: comparison with prohormone convertases
Y Berman1, L Juliano, L A Devi
1Department of Pharmacology, New York University School of Medicine, New York, USA.
Journal of Neurochemistry
|April 27, 1999
Summary
The dynorphin converting enzyme shows distinct cleavage specificity compared to prohormone convertases, preferring longer peptides with monobasic sites. This suggests multiple enzymes process peptide hormones at various cleavage sites.
Area of Science:
- Biochemistry
- Molecular Biology
- Enzymology
Background:
- Peptide hormones and neuropeptides undergo post-translational modification involving proteolytic cleavage.
- Dynorphin converting enzyme and prohormone convertases (like furin and prohormone convertase 1) are key enzymes in this processing.
- Understanding the substrate specificity of these enzymes is crucial for elucidating neuropeptide processing pathways.
Purpose of the Study:
- To characterize the cleavage specificity of the dynorphin converting endoprotease.
- To compare its specificity with that of prohormone convertases (furin and prohormone convertase 1).
- To investigate the enzyme's preference for monobasic versus dibasic cleavage sites and peptide length.
Main Methods:
- Utilized quench fluorescent peptide substrates to assess enzyme activity.
- Synthesized and tested peptides with defined cleavage sites (monobasic and dibasic).
- Employed matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF MS) to determine cleavage sites.
Main Results:
- The dynorphin converting enzyme efficiently cleaved a dynorphin B-29-derived peptide at a monobasic site, while furin and prohormone convertase 1 did not.
- A shorter peptide with a monobasic site was cleaved by the dynorphin converting enzyme and prohormone convertase 1, but not furin.
- Cleavage occurred N-terminal to the P1 Arg for the dynorphin converting enzyme and C-terminal for furin and prohormone convertase 1.
- The enzyme showed a preference for longer peptide substrates containing monobasic processing sites.
Conclusions:
- The cleavage specificity of the dynorphin converting enzyme is distinct from, yet related to, that of prohormone convertases.
- Multiple enzymes likely contribute to the processing of peptide hormones and neuropeptides at both monobasic and dibasic sites.
- The findings provide insights into the complex enzymatic machinery governing neuropeptide maturation.