Peptide Labeling with Improved ~(18)O Incorporation Method / 分析化学

In order to optimize the ~(18)O labeling method, two key aspects, peptide dispersion and trypsin deac tivation were discussed o The addition of Rapigest SF in H_2~('8)O and microwave heating enhanced labeling efficiency of α-casein digested peptides(~(18)O/~(16)O) ratio >99%).Chemical modification with tris(2-carboxyeth yl) phosphine (TCEP) and iodoacetamide (IAA) resulted in trypsin deactivated completely.No significant back-exchange from ~(18)O to ~(16)O was observed after labeling in 6 days.The experiment result with peptide mixture from showed that the improved method could be effectively used to label protein and peptide.