Determination of the acyl moieties of the antibiotic complex A40926 and their relation with the membrane lipids of the producer strain

Structures of the fatty acid characterizing the various components of A40926 were determined by gas chromatography/mass spectrometry on the methyl esters obtained by methanolysis of the complex. The results confirm the residues previously assigned to Factor A (n‐Undecanoic acid) and B (10‐methyl‐undecanoic acid) and establish the residues of Factor A1(9‐methyl‐decanoic acid), B1 (n‐dodecanoic acid), RS1 (8‐methyl‐nonanoic acid), RS2 (n‐decanoic acid), and RS3 (n‐tridecanoic acid). As the actinomadura species contain in their mycelia large quantities of C15‐C17 fatty acid residues as membrane phospholipids, these mycelia were saponified and the fatty acids obtained were analyzed as above. There is a close correlation beterrn the fatty acid content of A40923 complex and that of longer homologues in the producer mycelia.