Practical Protein Chemistry - A. Darbre 1989

Analysis of amino acid phenylthiohydantoins
Analytical Methods
Back-hydrolysis of PTH-amino acid derivatives

Several Reagents for reverse Hydrolysis (alkalis, hydriodic acid, methanesulfonic acid, Hydrochloric acid) are described. The most effective method involves hydrolyzing the sample with 6 M hydrochloric acid containing 0.1% tin(II) chloride [14]. The samples are dried in Glass hydrolysis ampoules, reagents are added, purged with nitrogen to remove oxygen, and sealed under vacuum. Hydrolysis is carried out at 150 °C for 4 h. The samples are then dried and their Amino Acid Composition is analyzed. This Procedure yields the corresponding Amino Acids in good yields from most thiazolinones. Thr is converted into $\alpha$-aminobutyric acid, Ser into Ala, and Trp into Gly. Therefore, a secondary analytical method (TLC, GLC, or HPLC) is required to identify Ser and Trp.



Last update: 06/08/2026

Editorial and Educational Adaptation: This material has been compiled based on the primary/original source text. The project team performed an editorial review, corrected technical inaccuracies, structured sections, and adapted the content for an educational format.

What was processed:

  • elimination of formatting defects (OCR errors, structural breaks, corrupted characters);
  • editorial organization of content;
  • standardization of terminology in accordance with academic sources;
  • verification of factual statements against the original source text.

All mentions of the author, publication year, and origin of the primary text have been preserved in accordance with the source.