Side the Edman degradation has become aut~mated~-~, improyep,ents in the methods for the rapid and ser~itive identification of the t&ohydantoin de-&a&-es of spfit off amino acids remain one of the main goals in the dete_mination of the primary StrUCtWfZ Of pK%inS and peptides. Apart frcm thin-Iayer chromatogaphy, the most comEnody Used techz@Ues far the SeparatioB and afSo fOF the qWfftitation Of ph@-(PTH) and methyl-(MTH) thiohydantoin derivatives obtained in sequential dega-d&on of proteins are gas-liquid chromatograp~_~~J and mass spectromeuys*S.
The main problems with afi of these methods are the separation and iderrtification Of the histidine and argfnine derivatives. These derivatives either have low volatility, are thermally decgaded during anal@ or require large amounts for identification by chemical method s. Hydrolysis back to the free amino acids and their determination in an amino acid anaIyzer are both faboriorrs and difEcult to carry orrt 0~ the micro-scale.
For high-sensitivity sequencing work, phenyl [%]isothiocyanate can be used'. However, this reagent doubles the costs of the sequencw chemicals in sorid-phase work.
~a& OI-I Our previous methods for very serzsitive and rapid m&i-sample identificafion of PTH-and MTH-amino acidss-~*, we have developed two solvent systems that are s&able for separating and identifying the arginine. h&id& and cysteic acid (CyS&H) deevafves-on polyamide sheets in an extremely short time.