Confirmation of the identity of the major phospholipid in human lens membranes.

PURPOSE

To confirm the identity of the major component of the human lens membranes proposed in 1994 to be dihydrosphingomyelin (DH-SPH).

METHODS

DH-SPH was prepared by catalytic hydrogenation of the double bond between carbons 4 and 5 of sphingomyelin (SPH). DH-SPH was characterized by phosphorus-31 (31P) and proton (1H) nuclear magnetic resonance (NMR) spectroscopy at different reaction times. The spectroscopic data were compared to those of the major component extracted from human lens membranes.

RESULTS

Both the 1H NMR and the 31P NMR spectral resonances of the prepared DH-SPH matched those for the once "unknown phospholipid" that constitutes approximately half the human lens phospholipids.

CONCLUSIONS

The match of the spectroscopic NMR data obtained for the DH-SPH prepared by hydrogenation of SPH and those for the major phospholipid isolated from the human lens membranes confirms the identity of this sphingolipid as D-erythro-4,5-dihydrosphingomyelin.