ISSN:
1432-1017
Keywords:
Key words Ceramides
;
2H-NMR
;
Membrane structure
;
PL-A2
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Physics
Notes:
Abstract The effects of a series of ceramide analogs with acyl chain lengths of 2, 6, 8 and 16 on the structure of dipalmitoylphosphatidylcholine (DPPC) bilayers and cobra venom phospholipase A2 (PL-A2) activity were studied using 2H-NMR and specific enzymatic assays. C2-ceramide did not induce a significant effect on the structure of DPPC bilayers and did not alter PL-A2 activity. C6- and C8-ceramides increased the ordering of the DPPC acyl chains, correlating with the inhibition of PL-A2 activity which was probably due to the increased lateral surface pressure. The long-chain C16-ceramide induced lateral phase separation of the bilayers into gel and liquid crystalline domains and activated PL-A2, as does natural ceramide (Huang et al. 1996). Taken together, the results strongly suggest a correlation between membrane defects induced by ceramide analogs and their effects on phospholipase A2 activity. Furthermore, the effects of short-chain ceramides on PL-A2 are different from those of natural ceramide, indicating that the cell-permeable short-chain ceramide analogs, widely used to study the sphingomyelin-dependent cellular signal transduction pathway, may not completely mimic the natural product.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/s002490050143
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