The surface area of very-low-density lipoproteins (VLDL) from the serum of
15 healthy donors, as well as the surface of artificial lipid particles, ha
ve been estimated. The artificial particles were prepared as a mixture of e
gg phosphatidylcholine and triolein. Two fluorescent probes - energy donor
and acceptor - were placed on the surface, and Forster's nonradiative energ
y transfer was measured; the transfer efficiency is a function of the surfa
ce area. The fluorescent probe K-68 (4-[5-(phenyloxazolyl-2)-1-pentadecyl)p
yridinium) was used as a donor, and DSP-12 (4-p-(dimethylamino)styryl-N-dod
ecylpyridinium) was used as an acceptor.
The specific surface area of the artificial lipid particles was estimated t
o be 0,585 +/- 0,015 nm(2) per one phosphatidylcholine molecule, which is b
y 15% less then in lipid bilayers.
The specific area of VLDL particles was 259 +/- 65 nm(2) per 1 g of total V
LDL. This value is close to the specific area of low-density lipoproteins (
LDL), and corresponds to the area of a spheric particle 10-12 nm in radius.
However, VLDL are assumed as much more large particles as compared with LD
L. Therefore, the new data of the VLDL surface area raise a problem of revi
sion of existing VLDL models.