Phospholipids of Clostridium butyricum III. FURTHER STUDIES ON THE ORIGIN OF THE ALDEHYDE CHAINS OF PLASMALOGENS

Abstract 1. The phosphatide plasmalogens of Clostridium butyricum, mainly ethanolamine and N-methylethanolamine plasmalogens, have been catalytically reduced and the resulting saturated glycerol ethers isolated as diacetate derivatives. Nuclear magnetic resonance spectra showed that the linkage of the ether chain was 1(3)-glycerol. Hydrolysis of the diacetates followed by periodate oxidation yielded close to an equivalent amount of formaldehyde, in confirmation of the 1(3)-linkage. 2. The aldehyde chains released from the phosphatide plasmalogens were analyzed by gas-liquid chromatography and shown to be similar in composition to the published composition of the 1-linked fatty acids of phosphatidylethanolamine from the same organism. 3. A study of the kinetics of incorporation of 1-14C-acetate into the phospholipid fraction of growing C. butyricum showed that the fatty acids had specific activities 5 to 6 times higher than those of the corresponding aldehydes after 5 to 10 min, and 2 to 3 times higher after 45 min. In the neutral lipid fraction, the esterified fatty acids had higher specific activities than the aldehydes up to 45 min after addition of 1-14C-acetate; subsequently, the ratios were reversed. Pathways from acetate to aldehydes to acids are not consistent with the data. The results are consistent with a derivation of the long chain aldehydes from the corresponding fatty acids. 4. Growing cells of C. butyricum incorporated 1-3H-1-14C-palmitaldehyde into fatty acids of plasmalogens with loss of 98% of the tritium, and into the aldehydes of plasmalogens with loss of about 85% of the tritium. Most, but not all, of the labeled palmitaldehyde appeared to have undergone oxidation prior to incorporation into plasmalogen-bound aldehyde.