Analysis for partition equilibrium of amino acid derivatives in aqueous/organic biphasic systems

Masamitsu Miyanaga, Koreyoshi Imamura, Keizo Tanaka, Takaharu Sakiyama, Kazuhiro Nakanishi

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2 Citations (Scopus)


The overall partition coefficients of the acid and amine components of amino acid derivatives, the substrates for proteinase-catalyzed synthesis of oligopeptide precursors, in an aqueous/organic biphasic system were studied both experimentally and theoretically. In a single-component system containing either an acid or amine component, the overall partition coefficient was well expressed by a model using the acid dissociation constant and partition coefficients for the non-ionized and ionized forms of the component. The overall partition coefficient in a binary-component system containing both acid and amine components was well simulated by the model when the formation of ion-pair complexes in the organic solvent phase was taken into consideration in addition to the partitioning of the non-ionized and ionized forms of the components. The formation of ion-pair complexes in the organic solvent phase was indicated by an analysis using Fourier transform infrared ray spectroscopy (FT-IR). In addition to the partition equilibrium, the aqueous-phase pH change after partitioning could be predicted by the model.

Original languageEnglish
Pages (from-to)651-658
Number of pages8
JournalJournal of Bioscience and Bioengineering
Issue number6
Publication statusPublished - 1999



  • Amino acid derivatives
  • Biphasic system
  • Enzymatic synthesis
  • FT-IR
  • Ion-pair formation
  • Partition

ASJC Scopus subject areas

  • Biotechnology
  • Bioengineering

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