Amino acid sequence and d/l-configuration determination of peptides utilizing liberated N-terminus phenylthiohydantoin amino acids

Comparison of four fluorescence Edman reagents with benzofurazan structure for the detection of thiazolinone amino acid derivatives

“…We have reported that the use of an aprotic acid, boron trifluoride (BF 3 ), facilitated the cyclization/cleavage reaction and provided higher yields of TZ-amino acids than TFA without racemization of the chiral center of amino acid. 11,[16][17][18] We used TFA since it has usually been used as the cyclization/cleavage reagent and the racemization of TZ-amino acids was not examined in this study. In order to observe the effect of the substituent group on the reaction, the time course of the yield of the TZ-Pro generated from TC-Pro-His-Leu was examined, since the N-terminal Pro-His linkage of a peptide is known to be particularly resistant to cleavage.…”

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

“…The generated PTH-amino acids were separated on the modified b-CD chiral stationary phases (Iida et al, 1998a). The modified Edman procedure was applied to a synthetic b-amyloid 1-16 as a model peptide, and the sequence and configuration determination of amino acids was achieved up to 12 residues.…”

“…Since the racemization in the conversion step occurred during the ring opening of ATZ amino acids and recyclization reaction to PTH amino acids (Iida et al, 1998a), ATZ amino acids were hydrolysed to phenylthiocarbamoyl (PTC) amino acids to suppress the racemization by the omission of the recyclization step. The Edman procedure with a conventional autoanalyser was modified, i.e., BF 3 was used instead of TFA in the cyclization/ cleavage step and the generated ATZ-amino acids were hydrolysed to PTC-amino acids by aqueous HCl solution.…”

Semi-automatic amino acid sequencing and D/L-configuration determination of peptides with detection of liberated N-terminal phenylthiocarbamoylamino acids

“…PTC-dipeptides (PTC-Asp-Ala, -Arg-Phe, -Glu-Ala, -Leu-Gly) were prepared as reported previously. 20 To sample tubes containing 10 nmol of PTC-dipeptide, 30 ml of 8 mmol dm 23 BF 3 in acetonitrile were added and the mixture was heated at 50 °C for 5 min. After drying under a stream of nitrogen, 10 ml of acetonitrile and 20 ml of 1 3 10 24 -1.0 mmol dm 23 HCl were added to the residue for hydrolysis.…”

“…The racemization from anilinothiazolinone-(ATZ-) amino acids to PTH-amino acids occurred in both the ring opening and recyclization steps in the conversion reaction. 20 Although the racemization was partly suppressed utilizing both BF 3 as the cleavage/cyclization reagent and HCl in methanol as Scheme 1 Reaction scheme for the Edman sequencing procedure. The asterisk donates a chiral center of carbon atom.…”