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Suggested functions for prolyl oligopeptidase: a puzzling paradox
Inger Brandt1, Simon Scharpé, Anne-Marie Lambeir
1Laboratory of Medical Biochemistry, Department of Pharmaceutical Sciences University of Antwerp, Universiteitsplein 1, Blg S6 B-2610 Antwerp (Wilrijk), Belgium.
Prolyl oligopeptidase (PO) is an enzyme whose exact physiological function remains unclear. Research using PO inhibitors and clinical samples reveals a paradox regarding its intracellular role in extracellular neuropeptide regulation.
Area of Science:
- Biochemistry
- Enzymology
- Molecular Biology
Background:
- Prolyl oligopeptidase (PO) is a post-proline cleaving endopeptidase.
- Its activity is limited to peptides under 30 amino acids.
- PO has been purified and characterized from mammalian and bacterial sources.
Purpose of the Study:
- To review the literature on the suggested functions of Prolyl oligopeptidase (PO).
- To highlight paradoxes and contradictions in current understanding of PO's physiological role.
- To explore how an intracellular enzyme may influence extracellular neuropeptides and signaling.
Main Methods:
- Literature review of existing studies on PO.
- Analysis of investigations using PO inhibitors.
- Examination of activity measurements in clinical samples.
- Review of (neuro)peptide degradation studies.
Main Results:
- Despite extensive characterization, the precise function of PO is not well-defined.
- Studies suggest PO influences extracellular neuropeptides, signal transduction, and secretion.
- A paradox exists concerning the intracellular localization and extracellular effects of PO.
Conclusions:
- The exact physiological role of Prolyl oligopeptidase (PO) remains an open question.
- Contradictions exist regarding PO's intracellular localization and its impact on extracellular processes.
- Further research is needed to resolve the paradoxes surrounding PO function.
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