Gas chromatographic and mass spectrometric analysis of molecular species of corynomycolic acids from <i>Corynebacterium ulcerans</i>

Abstract

IntroductionMycolic acids are very long chain/3-hydroxy fatty acids with carbon branch at the a-position and are known to be specific constituents of Mycobacteria [1-3], Corynebacteria [4][5][6] and Nocardia [7][8][9].The structural analysis of these types of fatty acids have been investigated extensively.However, because of their high boiling points and the instability at high temperatures, gas chromatographic analysis of the individual acids has not yet been fully established.Recently, we have succeeded in separating 15 molecular species of nocardomycolic acids and clarified the branched-chain structures of each component by the combined system of gas chromatography and mass spectrometry [ 10].The present paper describes that the homologues of corynomycolic acids obtained from Corynebacterium ulcerans can be also separated clearly into 12 major acids according to their total carbon numbers and the degree of unsaturation.The structural analysis of their trimethylsilyl derivatives revealed that the major fatty acids are C2o, C22, C24, C26, C2a, C30 and Ca2 saturated acids with smaller amounts of mono-and di-enoic acids.The branches at a-position are C~2 or C~4 in all cases.2.