THE CONDENSING EFFECTS OF EGG LECITHIN AND CHOLESTEROL ON TRIOLEIN MONOLAYERS ARE INHIBITED BY SUBSTITUTION OF ONE SATURATED ACYL-CHAIN IN THE TRIACYLGLYCEROL
Tg. Redgrave et al., THE CONDENSING EFFECTS OF EGG LECITHIN AND CHOLESTEROL ON TRIOLEIN MONOLAYERS ARE INHIBITED BY SUBSTITUTION OF ONE SATURATED ACYL-CHAIN IN THE TRIACYLGLYCEROL, Biochimica et biophysica acta, L. Lipids and lipid metabolism, 1211(2), 1994, pp. 229-233
Previous work showed that the clearance from plasma of chylomicron-lik
e emulsions injected intravenously was affected,by the acyl chains of
the constituent triacylglycerols. Compared with emulsions containing t
riolein (OOO) as the only triacylglycerol, clearances were decreased b
y a single saturated chain in emulsions containing 1,3-dioleoyl-2-stea
royl-sn-glycerol (OSO), 1,2-dioleoyl-3-stearoyl-sn-glycerol (OOS) or 1
-stearoyl-2,3-dioleoyl-sn-glycerol (SOO). The differences in clearance
may reflect physical differences at the oil-water interface related t
o chain interactions of the triacylglycerol structures with other lipi
d components. In the present work lipid monomolecular films at the air
-water interface were used to establish the capacity of OOO to interac
t with the pure synthetic triacylglycerols OOS and SOO, and the capaci
ty of OOS and SOO to eo-exist in monolayers of lecithin and of cholest
erol was compared with OOO. Substituting one oleoyl chain by a stearoy
l chain induced a 20% condensation in monomolecular films of the pure
triacylglycerols. Mixtures of OOO with either pure egg yolk phosphatid
ylcholine or cholesterol also showed substantial condensing effects. I
n contrast substituting one oleoyl chain by a stearoyl chain substanti
ally lessened the condensing effects. At surface pressures above the c
ollapse pressure of the pure triacylglycerols, substantially more OOO
than OOS or SOO was retained in mixed monolayers with phosphatidylchol
ine. These differences could underlie the effects on metabolism of sat
urated chains in emulsion triacylglycerols.