the stability of the diphenylindenonesulphonyl ( disyl ) derivatives of tryptophan , proline , hydroxyproline , histidine , serine , threonine and aspartic acid , as well as of glycine , alanine , alpha-amino butyric acid , phenylalanine , valine , leucine and isoleucine to acid hydrolysis is studied .
C0033382
proline
C0020388
hydroxyproline