Identification of 2-methyl-3-hydroxydecanoic and 2-methyl-3-hydroxytetradecanoic acids in the 'lipid X' fraction of the Bordetella pertussis endotoxin.

The 'lipid X' fraction, released from the Bordetella pertussis endotoxin upon treatment with trifluoroacetic acid of pH 3 at 50 degrees C, was shown to contain, in addition to 3-hydroxydecanoic, 3-hydroxydodecanoic, 3-hydroxytetradecanoic, and tetradec-2-enoic acids, 2-methyl-3-hydroxydecanoic-, and 2-methyl-3-hydroxytetradecanoic acids. The structure of these was established by gas-liquid chromatography/mass spectrometry.