TY - JOUR
T1 - Effect of phase transition on the distribution of membrane-associated particles in microsomes
AU - Duppel, Wilfried
AU - Dahl, Gerhard
PY - 1976/3/19
Y1 - 1976/3/19
N2 - 1. 1 Rat liver microsomes were studied by freeze-fracture electron microscopy. The distribution of membrane-associated particles indicated the right-side-out orientation of microsomal vesicles. Studies at different temperatures were performed. At 30°C membrane-associated particles are randomly distributed on membrane A-faces, while aggregations of particles are observed at 4°C. 2. 2 Aggregation is dependent on the cooling rates. It can be prevented by shock-freezing. 3. 3 Particle aggregation is also prevented by cholesterol, added to the microsomes in equal molar ratio to the microsomal phospholipid content. 4. 4 These findings suggest that particle aggregation is caused by a partial freezing-out of phospholipid molecules during the phase transition from the liquid-crystalline to the gel state. 5. 5 The results are discussed with respect to an observed increase in activation energy of microsomal drug monooxygenation at lower temperature.
AB - 1. 1 Rat liver microsomes were studied by freeze-fracture electron microscopy. The distribution of membrane-associated particles indicated the right-side-out orientation of microsomal vesicles. Studies at different temperatures were performed. At 30°C membrane-associated particles are randomly distributed on membrane A-faces, while aggregations of particles are observed at 4°C. 2. 2 Aggregation is dependent on the cooling rates. It can be prevented by shock-freezing. 3. 3 Particle aggregation is also prevented by cholesterol, added to the microsomes in equal molar ratio to the microsomal phospholipid content. 4. 4 These findings suggest that particle aggregation is caused by a partial freezing-out of phospholipid molecules during the phase transition from the liquid-crystalline to the gel state. 5. 5 The results are discussed with respect to an observed increase in activation energy of microsomal drug monooxygenation at lower temperature.
UR - http://www.scopus.com/inward/record.url?scp=0017237490&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0017237490&partnerID=8YFLogxK
U2 - 10.1016/0005-2736(76)90386-2
DO - 10.1016/0005-2736(76)90386-2
M3 - Article
C2 - 1268205
AN - SCOPUS:0017237490
VL - 426
SP - 408
EP - 417
JO - Biochimica et Biophysica Acta - Biomembranes
JF - Biochimica et Biophysica Acta - Biomembranes
SN - 0005-2736
IS - 3
ER -