Amino acid sequence and D/L‐configuration determination methods for D‐amino acid‐containing peptides in living organisms

D ‐amino acid‐containing peptides with biological activities have been isolated from invertebrates and amphibians, and partial racemization of amino acid residues in mammalian peptides associated with aging and diseases have been discussed. Here, we review the amino acid configuration determination methods in these peptides and recent progress of simultaneous determination method for sequence and configuration of amino acid residues. The applicability of C‐terminus sequence analysis and mass spectrometry to configuration determination of amino acids is also discussed.