Evaluation of the enantiomeric composition of amino acids in tobacco

Despite the fact that several studies have reported the concentrations of v arious free amino acids in tobacco, their enantiomeric composition is unkno wn. Both the absolute and enantiomeric compositions of proline, alanine, as paragine, aspartic acid, valine, methionine, leucine,and phenylalanine were determined for three strains of tobacco leaf, three types of smokeless tob acco, and six different blended filtered and nonfiltered reference cigarett es. Some of the highest levels of D-amino acids ever found in agricultural products were observed. Possible mechanisms for the production of these D-a mino acids are considered. The relevance of D-amino acids in tobacco is dis cussed. (C) 1999 Wiley-Liss, Inc.