Protein methylation identification method

The invention relates to a new protein methylation identification method. According to the present invention, the methylation site is labeled by using the novel heavy isotope labeled methionine, and the methylation peptide fragment analysis method integrating the methionine cell culture amino acid stable isotope labeling, the identification and extraction of the fragmentation spectrum of the methylation peptide fragment, and the spectrum peak demethylation treatment is developed, and is used in the large-scale analysis of methylated proteome; the amino acid labeling method can distinguish themethylated peptide fragment from the peptide fragment containing methionine, can identify and extract the fragmentation spectrum derived from the methylated peptide fragment, and can demethylate the fragmentation spectrum so as to obtain the spectrum of the unmethylated peptide fragment, and the peptide fragment sequence is determined by searching in a database so as to determine the modificationsite by binding to the spe