title: Proneurotensin 1-117, a stable neurotensin precursor fragment identified in human circulation.
abstract: Proneurotensin/neuromedin N (pro NT/NMN) is the common precursor of two biologically active peptides, neurotensin (NT) and neuromedin N (NMN). We have established antibodies against peptide sequences of the NT/NMN precursor and developed a sandwich immunoassay for the detection of pro NT/NMN immunoreactivity in human circulation. Endogenous pro NT/NMN immunoreactivity was enriched by affinity chromatography using antibodies against two different pro NT/NMN epitopes, and further purified by reversed phase HPLC. Mass spectrometry analysis revealed pro NT/NMN 1-117 as major pro NT/NMN immunoreactivity in human circulation. Pro NT/NMN 1-117 is detectable in serum from healthy individuals (n = 124; median 338.9 pmol/L). As known for NT, the release of pro NT/NMN 1-117 from the intestine into the circulation is stimulated by ingestion of an ordinary meal. Investigation of the pro NT/NMN 1-117 in vitro stability in human serum and plasma revealed that this molecule is stable for at least 48 h at room temperature. Since pro NT/NMN 1-117 is theoretically produced during precursor processing in stoichiometric amounts relative to NT and NMN, it could be a surrogate marker for the release of these bioactive peptides.
authors.affiliation: SphingoTec GmbH, Tulpenweg 6, D-16556 Borgsdorf, Germany. a.ernst@sphingotec.de
authors.forename: A
authors.initials: A
authors.lastname: Ernst
authors.forename: S
authors.initials: S
authors.lastname: Hellmich
authors.forename: A
authors.initials: A
authors.lastname: Bergmann
mesh_terms: D000595:Amino Acid Sequence; D002138:Calibration; D002846:Chromatography, Affinity; D000939:Epitopes / Q000737:chemistry; D006801:Humans; D007118:Immunoassay / Q000379:methods*; D007413:Intestinal Mucosa / Q000378:metabolism; D013058:Mass Spectrometry; D008969:Molecular Sequence Data; D009496:Neurotensin / Q000097:blood / Q000737:chemistry*; D010455:Peptides / Q000737:chemistry; D011498:Protein Precursors / Q000097:blood* / Q000737:chemistry; D017434:Protein Structure, Tertiary; D013696:Temperature
chemical_list: D000939:Epitopes; D010455:Peptides; D011498:Protein Precursors; C411471:proneurotensin; D009496:Neurotensin