title: Lysozyme fragmentation induced by gamma-radiolysis.
abstract: Irradiation of lysozyme in frozen states in the absence of oxygen induces specific fragmentation at defined sites along the backbone chain. This paper localizes radio-fragmentation sites by two methods. First, N-terminal sequencing of radiolysis fragments after separation by SDS-polyacrylamide gel electrophoresis and estimation of their molecular masses. Secondly, after purification of radiolysis fragments by reverse phase-HPLC and determination of their molecular mass by electro-spray-ionization mass-spectrometric analysis, combined to N-terminal sequencing and total amino acid analysis. Evidence for the breakage of the peptide bond itself (CO-NH) is given, with radio-fragmentation sites mostly found at the surface of irradiated lysozyme in solvent exposed loops and turns.
authors.affiliation: Hôpital Sainte-Justine, Département de Pédiatrie, Université de Montréal, Québec, Canada.
authors.forename: A
authors.initials: A
authors.lastname: Filali-Mouhim
authors.forename: M
authors.initials: M
authors.lastname: Audette
authors.forename: M
authors.initials: M
authors.lastname: St-Louis
authors.forename: L
authors.initials: L
authors.lastname: Thauvette
authors.forename: L
authors.initials: L
authors.lastname: Denoroy
authors.forename: F
authors.initials: F
authors.lastname: Penin
authors.forename: X
authors.initials: X
authors.lastname: Chen
authors.forename: N
authors.initials: N
authors.lastname: Rouleau
authors.forename: J P
authors.initials: JP
authors.lastname: Le Caer
authors.forename: J
authors.initials: J
authors.lastname: Rossier
authors.forename: M
authors.initials: M
authors.lastname: Potier
authors.forename: M
authors.initials: M
authors.lastname: Le Maire
mesh_terms: D002851:Chromatography, High Pressure Liquid; D004527:Egg Proteins / Q000737:chemistry* / Q000378:metabolism / Q000528:radiation effects*; D004591:Electrophoresis, Polyacrylamide Gel; D005615:Freezing; D005720:Gamma Rays; D009113:Muramidase / Q000737:chemistry* / Q000378:metabolism / Q000528:radiation effects*; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D012996:Solutions
chemical_list: D004527:Egg Proteins; D012996:Solutions; D009113:Muramidase