Analytical Sciences

Abstract − Analytical Sciences, 14(3), 507 (1998).

Nonbiological Complete Differentiation of the Enantiomeric Isomers of Amino Acids and Sugars by the Complexes of Gases with the Eutectic Compounds of Alkali Chlorides and Water
Department of Chemistry, Faculty of Science, Kanagawa University, 2946, Tsuchiya, Hiratsuka 259-1293, Japan
We have found that eutectic compounds of sodium chloride and water form complexes with oxygen, hydrogen sulfide and carbon dioxide in the aqueous 0.1 M NaCl solution. The oxygen complex differentiates between the enantiomeric isomers of amino acids and sugars. The direction of this differentiation agrees with that of biological systems in nature where only the L-isomers of amino acids are used to form proteins, while D-form sugars form polysaccharides. These results represent the first complete differentiation of enantiomeric isomers in an inorganic system, and were achieved without the aid of any in vivo biomaterials, such as enzymes. Other alkali chlorides were also examined. The eutectic compound of potassium chloride and water forms a similar oxygen complex which also differentiates the isomers of amino acids and sugars. However, the direction of this differentiation is opposite that in the case of sodium chloride. These results call for the special attention to the fact that the concentration of potassium ions in living cells is higher than that of sodium ions. The mechanism of these observations is not yet clear, but is likely to involve the structure of an aqueous solution of a specific concentration (0.1 M) of salt. The effects of various gases were also examined. Like oxy-gen, hydrogen sulfide also forms a complex with the eutectic compound of sodium chloride and water. This complex dif-ferentiates the isomers of amino acids and sugars in a similar manner to the way the oxygen complex dose. This finding suggests that the enantiomeric isomers of amino acids and sugars could be differentiated in an inorganic environment. Carbon dioxide also forms a complex with the eutectic compound of sodium chloride and water, but does not differentiate the isomers. (Keywords: Enantiomeric isomers, amino acid, sugar, eutectic compound, alkali chloride, water, dissolved gas)