Enzymatic synthesis of X-Phe-Leu-NH2 in low water content systems: Influence of the N-α protecting group and the reaction medium composition

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The influence of eight different N-terminal protecting groups (For, Ac, Boc, Fmoc, Mal, Pheac, Aloc and Z) on the α-chymotrypsin-catalyzed synthesis of the dipeptide derivative X-Phe-Leu-NH2 in organic media was studied. Groups such as Ac, For, Boc, Z, Mal, Pheac and Alloc always rendered good peptide yields (92% to 99%) either in acetonitrile or in ethyl acetate. Good correlations were found between molecular and physico-chemical characteristics of the N-α moiety such as the hydrophobicity (log P), ovality and dipole moment and the global reaction rate parameter k′. High k′ values were obtained with the less hydrophobic groups, Ac, For and Mal, that have ovality values close to one and the highest dipole moments. Furthermore, it was found that the relative rate of hydrolysis and aminolysis of the acyl-enzyme intermediate expressed as the partition parameter p is affected by the N-α moiety of the acyl donor. Correlations between this parameter and the dipole moment of the protecting group were observed.


External organisations
  • CSIC Centro de Investigación y Desarrollo Pascual Vila (CID)
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Biocatalysis and Enzyme Technology


  • Amino terminal protecting group, Hydrophobicity, Molecular ovality, Partition parameter, Peptide synthesis, α-Chymotrypsin
Original languageEnglish
Pages (from-to)189-196
Number of pages8
JournalBiochimica et Biophysica Acta (BBA)/Protein Structure and Molecular
Issue number2
Publication statusPublished - 1993 Jul 10
Publication categoryResearch