Coefficients de partage d’aminoacides, nucléobases, nucléosides et nucléotides dans un système solvant salin

Summary Partition coefficients of amino acids, nucleobases, nucleosides and nucleotides in a saline solvent system The behaviour of sixty-four nucleic compounds (bases, nucleosides, nucleoside-mono-, -di-, and -tri-phosphates) and eighteen amino acids was studied in a “saline solvent system” used for counter-current distribution of transfer ribonucleic acid, based on 1.50 M potassium phosphate pH 7.0, 2-methoxyethanol and 2-butoxyethanol. From the values of partition isotherms and partition coefficients K , measured in standard conditions at 20° and for 20% 2-butoxyethanol, it can be concluded that: (1) thiolation of bases decreases K , (2) phosphorylation of nucleosides accounts for negative, but additive effect on K , and (3) aliphatic lengthening of amino acids residues, N-alkylation, O-methylation, halogenation, C → N intracyclic substitution of bases, ribose → 3′-deoxyribose transformation increase K . The effect of these base or nucleoside substitutions is discussed and related to the mobility of tRNA separated by counter-current distribution.