title: Human alpha-fetoprotein primary structure: a mass spectrometric study.
abstract: The amino acid sequence of human alpha-fetoprotein, a 67-kDa protein present in mammalian embryonic serum, was verified by fast atom bombardment mass spectrometric (FAB/MS) analyses of three different enzymatic digests of the protein. Human alpha-fetoprotein obtained from a large-scale cell culture was digested with trypsin and V-8 protease either separately on two different samples or combined on the same one. The V-8 protease digest of the protein was partially fractionated by HPLC; the other samples were directly analyzed by FAB/MS without previous purification steps. About 90% of the alpha-fetoprotein amino acid sequence was verified by mass spectrometric analysis; this also confirmed that the cell-derived protein is identical with the hepatoma-derived protein. FAB analysis revealed that the N terminus of the mature protein is arginine rather than threonine, with the threonine occupying the second position. Therefore, the processing site of the alpha-fetoprotein signal peptide during maturation of the protein occurs at the N-terminal side of the arginine residue formerly indicated as residue-1. Thus mature alpha-fetoprotein contains 591 amino acids rather than 590.
authors.affiliation: Servizio di Spettrometria di Massa, Consiglio Nazionale delle Ricerche, Napoli, Italy.
authors.forename: P
authors.initials: P
authors.lastname: Pucci
authors.forename: R
authors.initials: R
authors.lastname: Siciliano
authors.forename: A
authors.initials: A
authors.lastname: Malorni
authors.forename: G
authors.initials: G
authors.lastname: Marino
authors.forename: M F
authors.initials: MF
authors.lastname: Tecce
authors.forename: C
authors.initials: C
authors.lastname: Ceccarini
authors.forename: B
authors.initials: B
authors.lastname: Terrana
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002460:Cell Line; D002851:Chromatography, High Pressure Liquid; D006801:Humans; D051379:Mice; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000302:isolation & purification; D051381:Rats; D012689:Sequence Homology, Nucleic Acid; D016339:Spectrometry, Mass, Fast Atom Bombardment; D000509:alpha-Fetoproteins / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification
chemical_list: D010446:Peptide Fragments; D000509:alpha-Fetoproteins