Faculty Collaboration Database

Protein-mediated exchange of synthetic phosphatidylcholines into synaptosomal membranes. Biochim Biophys Acta 1984 Apr 25;772(1):65-76

Date

04/25/1984

Pubmed ID

6712950

DOI

10.1016/0005-2736(84)90518-2

Scopus ID

2-s2.0-0021277073 (requires institutional sign-in at Scopus site)   3 Citations

Abstract

A phosphatidylcholine (PC) exchange protein from bovine liver was used to exchange endogenous synaptosomal membrane PC's with PC's of defined fatty-acid composition from phospholipid vesicles. Up to 50% of the total synaptosomal PC could be exchanged during a 3 h incubation with PC's which were in the liquid-crystalline state at the temperature of incubation (dimyristoyl-, dioleoyl- and dielaidoyl-PC). The biphasic kinetics of the exchange of 14C-labeled 1-palmitoyl-2-oleoyl-PC into isolated synaptic plasma membrane vesicles indicated that the half-time for transbilayer equilibrium of PC in these membranes was about 10 h. Hence, the observed 50% exchange of total synaptosomal PC probably represented nearly complete exchange of PC in the outer face of the synaptosomal plasma membrane. This extensive exchange was accomplished without apparent loss of synaptosomal function, including membrane potential and high-affinity uptake of choline and gamma-aminobutyric acid. PC's in the gel state (dipalmitoyl- and distearoyl-PC) could not be exchanged extensively into the synaptosomal membranes. However, from within gel-state distearoyl-PC liposomes, a trace amount of fluid 1-palmitoyl-2-oleoyl-PC (Tm less than 10 degrees C) could be preferentially exchanged into the synaptosomes at 32 degrees C with little transfer of the saturated PC.

Author List

North P, Fleischer S

Author

Paula E. North MD, PhD Professor in the Pathology department at Medical College of Wisconsin

MESH terms used to index this publication - Major topics in bold

Androgen-Binding Protein
Animals
Carrier Proteins
Choline
Fatty Acids
In Vitro Techniques
Membrane Lipids
Membrane Potentials
Phosphatidylcholines
Phospholipid Transfer Proteins
Prostatein
Rats
Secretoglobins
Sodium
Synaptic Membranes
Tissue Distribution
Uteroglobin
gamma-Aminobutyric Acid