title: Proenkephalin A 119-159, a stable proenkephalin A precursor fragment identified in human circulation.
abstract: In this report, we describe a newly developed sandwich immunoassay using antibodies against the proenkephalin A 119-159 peptide (PENK A 119-159). PENK A 119-159 immunoreactivity was detectable in the circulation of human blood donors and in cerebrospinal fluid (CSF) of patients without a neurologic disorder. The concentration was about 100 times higher in CSF than in serum. Analytical reversed phase HPLC revealed that PENK A 119-159 is the main immunoreactivity in human circulation and CSF. Moreover, PENK A 119-159 is stable in vitro for at least 48 h at room temperature as compared to the low stability of the peptides methionine- and leucine-enkephalin. This suggests the use of PENK A 119-159 measurement as surrogate molecule for the release of the mature peptides derived from proenkephalin A.
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: J
authors.initials: J
authors.lastname: Köhrle
authors.forename: A
authors.initials: A
authors.lastname: Bergmann
mesh_terms: D000595:Amino Acid Sequence; D002851:Chromatography, High Pressure Liquid; D004305:Dose-Response Relationship, Drug; D004745:Enkephalins / Q000097:blood* / Q000134:cerebrospinal fluid / Q000737:chemistry*; D006801:Humans; D007118:Immunoassay / Q000379:methods*; D008969:Molecular Sequence Data; D010455:Peptides / Q000737:chemistry; D011498:Protein Precursors / Q000097:blood* / Q000134:cerebrospinal fluid / Q000737:chemistry*
chemical_list: D004745:Enkephalins; D010455:Peptides; D011498:Protein Precursors; C029992:proenkephalin