With the increasingly widespread and in-depth application of peptides in the field of biomedicine, there is a growing demand for labeled and modified peptide types, as well as higher quality requirements. Stable isotope labeling is a typical example. Stable isotope labeling tracing can be used to study peptide metabolic pathways, and can track changes in the position and quantity of peptides containing isotope labeling in vivo or in vitro at any time. Isotope labeling has the advantages of high sensitivity, simple localization, and accurate quantification, which has led to increasing attention on isotope modification in the fields of medicine and biochemistry.

Stable isotope peptide classification:

1. N15 labeled isotopic peptides

2. C13 labeled isotopic peptides

3. N15 and C13 dual labeled isotopic peptides

The difference between isotopically labeled peptides and regular peptides is that one or several amino acids in their structure are replaced by C13 for C or N15 for N.