A CORRELATION FOR PREDICTING PARTITION-COEFFICIENTS IN AQUEOUS 2-PHASE SYSTEMS

Partition coefficients of amino acids and peptides are examined in poly(ethylene glycol)/magnesium sulfate systems. A correlation is proposed which relates the logarithm of the partition coefficient to the solute hydrophobicity and to the concentration difference between the phases of one of the phase-forming components. Partitioning data for several neutral amino acids were used to calculate individual amino acid residue hydrophobicities. These hydrophobicities were then used successfully to predict the partition coefficients of peptides in the same phase systems. The predicted and observed partition coefficients are compared for several peptides composed of two to four amino acid residues.