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A partially purified calmodulin (CaM)-sensitive adenylate cyclase from bovine cerebral cortex was reconstituted with a series of phosphatidylcholine liposomes having variable fatty acid composition. The enzyme was successfully associated with dimyristoyl, dipalmitoyl, distearoyl, and dioleoylphosphatidylcholine liposomes. The specific activity of the enzyme in the various liposomes varied over a 4.6-fold range indicating some degree of specificity for fatty acid composition. The adenylate cyclase-liposome preparation retained sensitivity to both CaM and 5'-guanylylimidodiphosphate (GppNHp). Arrhenius plots of enzyme activity in the four different liposome preparations all exhibited a pronounced discontinuity at 30 degrees C +/- 2, even though the bulk-phase thermal transition points for the liposomes varied from -20 to 54 degrees C. Fluorescence anisotropy studies of reconstituted liposome systems illustrated that incorporation of protein did not alter the normal-phase transition point of these lipids. Since Arrhenius plots of the enzyme in Lubrol PX, prior to reconstitution with lipids, were strictly linear, it is concluded that the breaks at 30 degrees C may be the effect of a local enzyme-phospholipid environment. It appears that this adenylate cyclase is not particularly sensitive to phase transitions of the bulk lipid phase. The phospholipid reconstituted enzyme system appears suitable for examination of the influence of lipids on the CaM-sensitive adenylate cyclase.
R E Yeager, and
W Heideman, and
B B Olwin, and
C H Keller, and
J W Schmidt, and
R L Shattuck, and
D R Storm
January 1987,
Methods in enzymology,
R E Yeager, and
W Heideman, and
B B Olwin, and
C H Keller, and
J W Schmidt, and
R L Shattuck, and
D R Storm
July 1986,
Journal of neurochemistry,
R E Yeager, and
W Heideman, and
B B Olwin, and
C H Keller, and
J W Schmidt, and
R L Shattuck, and
D R Storm
January 1979,
The Journal of biological chemistry,
R E Yeager, and
W Heideman, and
B B Olwin, and
C H Keller, and
J W Schmidt, and
R L Shattuck, and
D R Storm
January 1980,
Annals of the New York Academy of Sciences,
R E Yeager, and
W Heideman, and
B B Olwin, and
C H Keller, and
J W Schmidt, and
R L Shattuck, and
D R Storm
January 1991,
Methods in enzymology,
R E Yeager, and
W Heideman, and
B B Olwin, and
C H Keller, and
J W Schmidt, and
R L Shattuck, and
D R Storm
June 1989,
Journal of protein chemistry,
R E Yeager, and
W Heideman, and
B B Olwin, and
C H Keller, and
J W Schmidt, and
R L Shattuck, and
D R Storm
October 1981,
The Journal of biological chemistry,
R E Yeager, and
W Heideman, and
B B Olwin, and
C H Keller, and
J W Schmidt, and
R L Shattuck, and
D R Storm
July 1987,
Biochemistry,
R E Yeager, and
W Heideman, and
B B Olwin, and
C H Keller, and
J W Schmidt, and
R L Shattuck, and
D R Storm
March 1982,
Proceedings of the National Academy of Sciences of the United States of America,
R E Yeager, and
W Heideman, and
B B Olwin, and
C H Keller, and
J W Schmidt, and
R L Shattuck, and
D R Storm
May 1988,
The Journal of biological chemistry,
