THE USE OF MALDI MASS-SPECTROMETRY TO CHARACTERIZE SYNTHETIC PROTEIN CONJUGATES

MALDI mass spectrometry has been used to study the conjugation of two small molecules to hen egg white lysozyme and human serum albumin. Hap ten densities were determined with both proteins. Synthetic peptide mi xtures, designed to eliminate the need for subsequent sequencing exper iments, were used to assess the potential reactivities of various amin o acid side chains in proteins. Selective hydrolysis reactions were al so used to differentiate ester and amide conjugates, which are expecte d to have quite different in vivo stabilities. Finally, MALDI was used to follow the kinetics of protein conjugation reactions, even for rea ctions having initial rates differing by as much as three orders of ma gnitude. (C) 1997 Elsevier Science B.V.