CHARACTERIZATION OF A SYNTHETIC 37-RESIDUE FRAGMENT OF A MONOCLONAL-ANTIBODY AGAINST HERPES-VIRUS BY CAPILLARY ELECTROPHORESIS ELECTROSPRAY(IONSPRAY) MASS-SPECTROMETRY AND CF-252 PLASMA DESORPTION MASS-SPECTROMETRY

A peptide comprising 37 amino acids of the antigen binding site of a m onoclonal antibody directed against glycoprotein D of herpes simplex v irus was synthesized. The synthetic peptide and the impurities formed in the synthesis were characterized by capillary electrophoresis/ionsp ray mass spectrometry and by Cf-252 plasma desorption-time of flight m ass spectrometry. The measured average molecular mass of the synthetic peptide was 4627.16 De, which was only 0.08 Da higher than the calcul ated value (4627.08 Da). The plasma desorption mass spectrum of the sy nthetic peptide showed a protonated molecule at mit 4624.1, which was 4 Da lower than the calculated one (4628.09 Da). The amino acid sequen ce of the peptide was confirmed in part by electrospray (ionspray) mas s spectrometry using a high nozzle skimmer voltage difference. Five im purities were separated and identified by capillary electrophoresis/ma ss spectrometry and two of them also appeared in the plasma desorption mass spectrum.