Amino acid sequences interconvertability

Tantomerization (Section 18.2) An isomerization by which tautomers are rapidly interconverted, as in keto-enol tantomerization. Tautomers (Section 18.2) Constitutional isomers that are easily interconverted. Keto and enol tautomers, for example, are rapidly interconverted in the presence of acids and bases. Terminal residue analysis (Section 24.5) Methods used to determine the sequence of amino acids in a peptide by reactions involving the N- and C-terminal residues. 

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