title: Hydrolytic cleavage of pyroglutamyl-peptide bond. V. selective removal of pyroglutamic acid from biologically active pyroglutamylpeptides in high concentrations of aqueous methanesulfonic acid.
abstract: Application of aqueous methanesulfonic acid (MSA) for selective chemical removal of pyroglutamic acid (pGlu) residue from five biologically active pyroglutamyl-peptides (pGlu-X-peptides, X=amino acid residue at position 2) was examined. Gonadotropin releasing hormone (Gn-RH), dog neuromedin U-8 (d-NMU-8), physalaemin (PH), a bradykinin potentiating peptide (BPP-5a) and neurotensin (NT) as pGlu-X-peptides were incubated in either 70% or 90% aqueous MSA at 25 degrees C. HPLC analysis of the incubation solutions showed that the main decomposition product was H-X-peptide derived from each pGlu-X-peptide by the removal of pGlu. The results revealed that the pGlu-X peptide bond had higher susceptibility than various internal amide bonds in the five peptides examined, including the Trp-Ser bond in Gn-RH, the C-terminal Asn-NH(2) in d-NMU-8, and the Asp-Pro bond in PH, whose acid susceptibility is well known. Thus, mild hydrolysis with high concentrations of aqueous MSA may be applicable to chemically selective removal of pGlu from pGlu-X-peptides for structural examinations.
authors.affiliation: Faculty of Pharmaceutical Sciences, Hokuriku University, Kanagawa-machi, Kanazawa 920-1181, Japan.
authors.forename: Junko
authors.initials: J
authors.lastname: Kobayashi
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Ohki
authors.forename: Keiko
authors.initials: K
authors.lastname: Okimura
authors.forename: Tadashi
authors.initials: T
authors.lastname: Hashimoto
authors.forename: Naoki
authors.initials: N
authors.lastname: Sakura
mesh_terms: D000818:Animals; D001920:Bradykinin / Q000378:metabolism; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D004285:Dogs; D007987:Gonadotropin-Releasing Hormone / Q000378:metabolism; D006801:Humans; D006868:Hydrolysis; D009479:Neuropeptides / Q000378:metabolism; D009496:Neurotensin / Q000378:metabolism; D010455:Peptides / Q000378:metabolism*; D011761:Pyrrolidonecarboxylic Acid / Q000378:metabolism*; D053719:Tandem Mass Spectrometry
chemical_list: D009479:Neuropeptides; D010455:Peptides; D007987:Gonadotropin-Releasing Hormone; D009496:Neurotensin; C046270:neuromedin U 8; D001920:Bradykinin; D011761:Pyrrolidonecarboxylic Acid