Identification of human placental wheat germ agglutinin-immunoreactive protein by mass spectrometry.
A preparation of polyclonal antibodies to human placental calcium-dependent, carbohydrate-binding glycoprotein, previously identified as wheat germ agglutinin-immunoreactive protein, was applied as the ligand in an immunoaffinity procedure. Following electrophoretic separation of purified material, the specific 66-kDa antigen band was excised and subjected to in-gel protein cleavage. Matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) analysis of the tryptic digest yielded 42 isotopically resolved peptide fragments from mass 860 to 2,690. Empirical data from MALDI-MS were analyzed by computer assistance using ProteoMetrics PROFOUND software. Protein candidates reported in the specified identification database search are discussed in relation to the biochemical characteristics of the protein analyzed and its possible antigenic relatedness to wheat germ agglutinin. We speculate that a fibulin-like member of the epidermal growth factor-repeat protein family might be selected as a positive match.
Janković
Miroslava
M
Institute for the Application of Nuclear Energy-INEP, Banatska 31b, 11080 Zemun, Yugoslavia. miraj@inep.co.yu
D000595:Amino Acid Sequence; D000906:Antibodies / Q000276:immunology; D002846:Chromatography, Affinity; D004591:Electrophoresis, Polyacrylamide Gel; D006801:Humans; D008024:Ligands; D008969:Molecular Sequence Data; D010449:Peptide Mapping; D010920:Placenta / Q000737:chemistry*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*; D014909:Wheat Germ Agglutinins / Q000276:immunology / Q000302:isolation & purification*
D000906:Antibodies; D008024:Ligands; D014909:Wheat Germ Agglutinins