Stability of tryptophan-containing peptides in the presence of an L-ascorbic acid-ferric ion system
1995
Steinhart, H. | Meyer, K. | Vollmar, M.
The stability of free or peptide-bound L-tryptophan (Trp) was studied in the presence of an L-ascorbic acid-ferric ion system. Trp was present in three different forms of peptides: in peptides with amino terminal Trp, with carboxy-terminal Trp, or with Trp in a middle position. These peptides were synthesized using fluorenylmethoxycarbonyl polyamide solid phase active ester chemistry. Decreases in peptide content as well as the stability of neighboring amino acids were determined. In each case the rate of oxidation of amino-terminal Trp was higher than in the corresponding peptide with carboxy-terminal Trp. Losses of Trp and the peptides themselves depend upon neighboring amino acid residues.
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