Araiso T, Saito H, Shirahama H, Koyama T
Section of Physiology, Hokkaido Univ. Sapporo, Japan.
Biorheology. 1990;27(3-4):375-87. doi: 10.3233/bir-1990-273-414.
The viscosity and the molecular motion of phospholipid molecule in biological and artificial phospholipid bilayers were studied using picosecond fluorescence depolarization method with rod-like fluorophore, DPH. From the relationship between the viscosity in the lipid bilayer and the free space of phospholipid acyl-chain, it is concluded that the viscosity is determined mainly by the range of wobbling motion of the acyl-chain. Motion of polar head group was also measured by the same method with a newly synthesized fluorescent phospholipid, dipalmitoyl-phosphatidyl-umbelliferone. The rate and the range in the motion of head group were faster and larger than those of acyl-chain and gave the viscosity of head group layer to be 0.03 poise, which was about one tenth of that of acyl-chain layer in the liquid crystalline phase. This fact indicates that the head group layer would not resist the lateral diffusion of molecules in membrane and that the lateral diffusion rate of molecules could be estimated from the viscosity in the acyl-chain layer.
使用带有棒状荧光团DPH的皮秒荧光去偏振方法，研究了生物和人工磷脂双层中磷脂分子的粘度和分子运动。从脂质双层中的粘度与磷脂酰基链自由空间的关系可以得出结论，粘度主要由酰基链摆动运动的范围决定。还使用新合成的荧光磷脂二棕榈酰磷脂酰伞形酮，通过相同方法测量了极性头部基团的运动。头部基团运动的速率和范围比酰基链的更快、更大，并且头部基团层的粘度为0.03泊，约为液晶相中酰基链层粘度的十分之一。这一事实表明，头部基团层不会阻碍膜中分子的横向扩散，并且分子的横向扩散速率可以根据酰基链层中的粘度来估计。
