Verteilung von markierten Molekeln in Kristallsuspensionen als analytisch und präparativ ausnutzbare Methode der Tracerchemie: Untersuchungen mit14C-markierten Aminosäuren

Abstract

The partition between solution and solid phase of several 14C-labeled amino acids initially present in tracer amounts in the solution phase of stirred suspensions of crystalline amino acids was studied. The partitions examined were stereospecific since the labeled L-amino acid molecules were readily taken up from the solution phase by the corresponding L-crystals whereas the isomeric D-CryStdS incorporated the labeled L-molecules at a reduced rate (as exemplified by alanine and serine) or did not incorporate labeled L-molecules at all. If a sufficiently large excess of crystalline phase as compared to the amount of solute is employed and if incorporation takes place the radioactivity in solution decreases to a small and practically constant fraction of its initial value. The incorporation of various labeled L-amino acids into a crystalline L-leucine phase was also studied. The rate of uptake was characteristic for each amino acid. The partition experiments can be performed easily and may be used for analytical and preparative purposes. From studies of leucine and tyrosine systems it is concluded that the partitions observed depend on dissolution and crystallisation processes coupled with crystal fragments which are present or formed during the stirring in the crystal suspension.