title: Letter: Specific isotope labeling for the identification of free N-terminal peptide of proteins separated by polyacrylamide gel electrophoresis.
abstract: We report here a method for the identification of free N-terminal peptide of in gel digested isolated proteins. It is based in the difference between the isotopic ion distribution of N-terminal peptide and internal peptides. After guanidination of lysine residues, the primary amino groups of the gel-entrapped protein are blocked with an equimolar mixture of normal and deuterated acetic anhydride. Upon MS analysis internal peptides display a normal isotopic ion distribution while the N-terminal peptide shows a complex isotopic ion distribution.
authors.forename: Aniel
authors.initials: A
authors.lastname: Sanchez
authors.forename: Yassel
authors.initials: Y
authors.lastname: Ramos
authors.forename: Yanni
authors.initials: Y
authors.lastname: Solano
authors.forename: Luis Javier
authors.initials: LJ
authors.lastname: González
authors.forename: Lazaro
authors.initials: L
authors.lastname: Betancourt
authors.forename: Jeovanis
authors.initials: J
authors.lastname: Gil
authors.forename: Gabriel
authors.initials: G
authors.lastname: Padron
authors.forename: Vladimir
authors.initials: V
authors.lastname: Besada
mesh_terms: D000089:Acetic Anhydrides / Q000737:chemistry; D003903:Deuterium; D004591:Electrophoresis, Polyacrylamide Gel; D007553:Isotope Labeling / Q000379:methods*; D010455:Peptides / Q000737:chemistry*; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*
chemical_list: D000089:Acetic Anhydrides; D010455:Peptides; C031800:acetic anhydride; D003903:Deuterium