Externalization of phosphatidylserine from inner to outer layer may alter the effect of plant sterols on human erythrocyte membrane : the Langmuir monolayer studies
Externalization of phosphatidylserine from inner to outer layer may alter the effect of plant sterols on human erythrocyte membrane : the Langmuir monolayer studies
Externalization of phosphatidylserine from inner to outer layer may alter the effect of plant sterols on human erythrocyte membrane : the Langmuir monolayer studies
One of the factors, which can strongly modify the cell membrane composition, is disordering in membrane
asymmetry, resulting from redistribution of lipids from inner to outer layer. Such a disturbance may affect
the behavior of various biologically active compounds incorporating into membranes. In this contribution,
the relationship between the amounts of phosphatidylserine (PS) in the model outer layer of human eryth-
rocyte (RBC) membrane and the effect induced by a plant sterol (
β
-sitosterol) was veri
fi
ed. The experiments
were performed on multicomponent Langmuir
fi
lms imitating red blood cell (RBC) membrane, differing in
the contents of PS (0%; 5% and 10%) into which the plant sterol was incorporated in various concentrations.
The analysis of experimental results (surface pressure
–
area isotherms complemented with Brewster Angle
Microscopy (BAM) proved that the presence of phosphatidylserine molecules, depending on their contents
in the mixed monolayer mimicking RBC membrane, changes its properties and exerts in
fl
uence on the effect
of plant sterol on the model system. The addition of phytosterol into the monolayer that lacks or contains
only 5% of PS was found to be of rather weak effect on the properties of the system. However, in the case
of the model membrane containing the increased amount (10%) of PS, the incorporation of plant sterol
strongly affects the interactions between molecules and caused thermodynamic destabilization of the mono-
layer imitating RBC membrane. These results allow one to suggest that externalization of phosphatidyserine
to the outer membrane lea
fl
et may differentiate the effect of plant sterols on cell membranes of various
origins
keywords in English:
model outer layer of human erythrocyte, langmuir film, (RBC) membrane, Brewster angle microscopy, plant sterol, Phosphatidylserine
affiliation:
Wydział Chemii : Zakład Chemii Ogólnej, Wydział Chemii : Zakład Chemii Środowiska