Related Experiment Video
Updated: Mar 18, 2026

Cell Subtype-specific Analysis of Neuronal Membrane Proteasome in Somatosensory Neurons
Published on: October 10, 2025
A Group of Weakly Bound to Neurons Extracellular Metallopeptidases (NEMPs)
Ekaterina S Kropotova1,2, Mark I Mosevitsky3,4
1Division of Molecular Biophysics, Petersburg Nuclear Physics Institute, Gatchina, 188300, Russia.
Abstract:
We have found that isolated from mammalian brain (rat, bovine) axonal endings (synaptosomes) degrade peptides of different composition. With the use of low concentration of non ionic detergent Triton X-100 (0.05-0.1 %) four low specific metallopeptidases were detached from synaptosomes. These peptidases were named Neuronal EctoMetalloPeptidases (NEMPs). Using specially designed test-peptides they were characterized as: carboxypeptidase (NEMP1), aminopeptidase (NEMP2) and endopeptidases NEMP3 and NEMP4. NEMPs are true peptidases (oligopeptidases), because they are able efficiently degrade peptides containing less than 40 amino acid residues. Specific properties of some NEMPs were revealed. NEMP1 is a small protein (molecular mass of about 10 kDa), which tends to dynamic oligomerization. NEMP3 needs activation. Some amino acids activate this enzyme. As far as we know, these properties were not ascribed to the known similarly localized peptidases. A possible physiological function of low specific NEMPs is participation in control of wide range of neuropeptides secreted in the synaptic cleft. However, NEMPs also due to their low specificity can destroy introduced in brain therapeutic peptides. The data obtained in this study open new opportunities for the protection of synthetic therapeutic peptides in brain and, possibly, in other tissues.
Related Concept Videos
Ligand-Gated Ion Channel Receptor: Gating Mechanism
Ligand-gated Ion Channels
Three Subfamilies of Ligand-gated Ion Channels
Ligand-gated ion channels fall into three subfamilies. The 'Cys-loop' includes the nicotinic acetylcholine receptors, γ-aminobutyric acid (GABA), glycine, and 5-hydroxytryptamine receptors. The second one is the 'Pore-loop' channels that...
Neurochemical Transmission: Sites of Drug Action
Chemical Synapses
Because chemical synapses depend on the release of neurotransmitter molecules from synaptic vesicles to pass on their signal, there is an approximately one millisecond delay between when the axon potential reaches the presynaptic terminal and when the neurotransmitter leads to opening of postsynaptic ion channels. Additionally, this signaling is...
Chemical Synapses
Because chemical synapses depend on the release of neurotransmitter molecules from synaptic vesicles to pass on their signal, there is an approximately one millisecond delay between when the axon potential reaches the presynaptic terminal and when the neurotransmitter leads to opening of postsynaptic ion channels. Additionally, this signaling is...
Role of Matrix Metalloproteases in Degradation of ECM

