Effect of alcohols on the phase transitions of dihexadecylphosphatidylcholine.
We have systematically investigated the effect of short chain alcohols (methanol to n-propanol) on the phase transitions of 1,2-dihexadecylphosphatidylcholine (DHPC), a lipid that forms a stable interdigitated gel phase (L beta I) in aqueous solution. The temperature of the low-temperature L beta I to P beta' phase transition of DHPC was found to increase with alcohol concentration, showing that alcohol interacts preferentially with the interdigitated phase relative to the non-interdigitated gel. The main transition of DHPC exhibited a biphasic effect of alcohol concentration similar to that previously observed with DPPC (Rowe, E.S. (1983) Biochemistry 22,3299-3305). As alcohol concentration is increased the lower L beta I to P beta' and main P beta' to L alpha transitions of DHPC merge at the threshold concentration of the biphasic effect, so that above this concentration there is one phase transition from L beta I directly to L alpha. This is analogous to DPPC above its biphasic threshold. Similar to DPPC, the transition between L beta I and L alpha exhibits marked hysteresis.
Veiro
J A
JA
University of Kansas Medical Center, Kansas City.
Nambi
P
P
Rowe
E S
ES
D000438:Alcohols / Q000494:pharmacology*; D010742:Phospholipid Ethers / Q000378:metabolism*; D013696:Temperature
C052298:1,2-dihexadecyl-sn-glycero-3-phosphocholine; D000438:Alcohols; D010742:Phospholipid Ethers