title: Peptidomics of prolyl endopeptidase in the central nervous system.
abstract: Prolyl endopeptidase (Prep) is a member of the prolyl peptidase family and is of interest because of its unique biochemistry and connections to cognitive function. Using an unbiased mass spectrometry (MS)-based peptidomics platform, we identified Prep-regulated peptides in the central nervous system (CNS) of mice by measuring changes in the peptidome as a function of Prep activity. This approach was validated by the identification of known Prep substrates, such as the neuropeptide substance P and thymosin-beta4, the precursor to the bioactive peptide Ac-SDKP. In addition to these known substrates, we also discovered that Prep regulates many additional peptides, including additional bioactive peptides and proline rich peptides (PRPs). Biochemical experiments confirmed that some of these Prep-regulated peptides are indeed substrates of the enzyme. Moreover, these experiments also supported the known preference of Prep for shorter peptides while revealing a previously unknown cleavage site specificity of Prep when processing certain multi-proline-containing peptides, including PRPs. The discovery of Prep-regulated peptides implicates Prep in new biological pathways and provides insights into the biochemistry of this enzyme.
authors.affiliation: Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02138, USA.
authors.forename: Whitney M
authors.initials: WM
authors.lastname: Nolte
authors.forename: Debarati M
authors.initials: DM
authors.lastname: Tagore
authors.forename: William S
authors.initials: WS
authors.lastname: Lane
authors.forename: Alan
authors.initials: A
authors.lastname: Saghatelian
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D053961:Azabicyclo Compounds / Q000494:pharmacology; D019556:COS Cells; D015740:Calcitonin Gene-Related Peptide / Q000502:physiology; D002522:Chlorocebus aethiops; D002853:Chromatography, Liquid; D051379:Mice; D008810:Mice, Inbred C57BL; D008969:Molecular Sequence Data; D010455:Peptides / Q000037:antagonists & inhibitors / Q000737:chemistry* / Q000378:metabolism; D000085822:Prolyl Oligopeptidases; D040901:Proteomics / Q000379:methods*; D012697:Serine Endopeptidases / Q000737:chemistry* / Q000378:metabolism; D015842:Serine Proteinase Inhibitors / Q000494:pharmacology; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013116:Spinal Cord / Q000187:drug effects / Q000201:enzymology*; D013379:Substrate Specificity / Q000187:drug effects; D053719:Tandem Mass Spectrometry
chemical_list: D053961:Azabicyclo Compounds; D010455:Peptides; D015842:Serine Proteinase Inhibitors; D012697:Serine Endopeptidases; D000085822:Prolyl Oligopeptidases; D015740:Calcitonin Gene-Related Peptide