The presence of acyl-CoA: cholesterol acyltransferase in Tetrahymena pyriformis W.
1. The esterification of cholesterol was studied in Tetrahymena pyriformis an organism which does not synthesize sterols nor are sterols required for growth. 2. Microsomes catalyzed the esterification of cholesterol in the presence of oleoyl-CoA but not oleic acid or lecithin. 3. The enzyme has a similar sterol substrate specificity to that of mammalian acyl-CoA: cholesterol acyltransferase (ACAT) and was inhibited by the specific ACAT inhibitor 58-035. 4. The enzyme is constitutive since activity was observed in cells grown in sterol-free medium when cholesterol was added to the in vitro assay.
Billheimer
J T
JT
Cardiovascular Group, E.I. Du Pont de Nemours and Company, Wilmington, DE 19898.
Landrey
J R
JR
Conner
R L
RL
D000818:Animals; D004951:Esterification; D008861:Microsomes / Q000378:metabolism; D051381:Rats; D002785:Sterol O-Acyltransferase / Q000032:analysis* / Q000037:antagonists & inhibitors; D013379:Substrate Specificity; D013769:Tetrahymena pyriformis / Q000032:analysis*
D002785:Sterol O-Acyltransferase