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Dynorphin A(1–17) biotransformation in striatum of freely moving rats using microdialysis and matrix‐assisted laser desorption/ionization mass spectrometry
Author(s) -
Reed Brian,
Zhang Yong,
Chait Brian T.,
Kreek Mary Jeanne
Publication year - 2003
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1046/j.1471-4159.2003.01859.x
Subject(s) - chemistry , dynorphin , mass spectrometry , dynorphin a , chromatography , biotransformation , peptide , tandem mass spectrometry , matrix assisted laser desorption/ionization , microdialysis , opioid peptide , biochemistry , desorption , opioid , enzyme , organic chemistry , receptor , extracellular , adsorption
The biotransformation of the opioid peptide dynorphin A(1–17) was investigated in striatum of freely moving Fischer rats, by direct infusion of this peptide, followed by recovery of the resulting biotransformation products via microdialysis and identification using matrix‐assisted laser desorption/ionization mass spectrometry. The observed peptides are consistent with enzymatic cleavage at the Arg 7 ‐Ile 8 position of dynorphin A(1–17), followed by terminal degradation of the resulting dynorphin A(1–7) and dynorphin A(8–17) peptides. Unexpectedly, novel post‐translational modifications were found on C‐terminal fragments of dynorphin A(1–17). Using tandem mass spectrometry, a covalent modification of mass 172 Da, the nature of which is not understood, was found on the tryptophan residue of C‐terminal fragments (Trp 14 ). Additional modifications, of mass 42 and 113 Da, were also found on the N‐terminus (Ile 8 or Pro 10 ) of these same C‐terminal fragments. The role of these modifications of C‐terminal fragments has not yet been characterized.