The non-covalent interaction between a series of N-phosphoryl dipeptides (or methyl esters) and lysozyme was studied by using ESI-MS. The effects of different groups of N-phosphoryl dipeptides (or methyl esters) were compared. The results show that —OH is very important for the interaction, and the aromatic ring has double functions on the interaction because of its steric hindrance. The linked —OH and aromatic ring showed synergistic reaction and enhanced their interaction. Moreover, the size of the molecule and steric hindrance showed obvious effects on the interaction, while the configuration, sequence and length of carbon chains (increasing 1～2 C) of amino acid residue in the phosphoryl oligopeptides showed little effects on the interaction under ESI-MS conditions. Phosphoryl oligopeptides having extended construction, increasing molecular flexibility and smaller spatial hindrance could contract the protein configuration in solution, and the contractive protein molecule integrated with the smaller phosphoryl oligopeptide molecules more easily.

Key words: ESI-MS, N-phosphoryl dipeptide (or methyl esters), lysozyme, non-covalent interaction