EFFECT OF ACETIC ANHYDRIDE IN ANHYDROUS DIOXANE ON C-TERMINAL RESIDUES OF PEPTIDES.

The reaction of 20 dipeptides, 2 tripeptides, and 1 heptapeptide with acetic anhydride in anhydrous dioxane was studied. After 6N HC1 hydrolysis the yield of the C-terminal residue was less than that of the penultimate residue in all peptides except three of the dipeptides. The yield of the penultimate residue in the two tripeptides was less than that of the N-terminal residue. Tyrosyl arginine yielded ornithine to partly account for the lost arginine. These results suggest that the acetic anhydride-dioxane reaction can be used as a subtractive method for identifying C-terminal amino acid residues in some peptides. (Author)