Control of Cholesterol Biosynthesis by a Plasma Apo-lipoprotein

MEVALONIC acid (MVA) is well known as a precursor of cholesterol 1 , and it is also established that squalene is an intermediate in the biosynthesis of cholesterol 2,3 . When liver microsomes plus the cell sap are incubated with 2- 14 C mevalonic acid in air, most of the radioactivity is incorporated into cholesterol and very little radioactivity is associated with squalene. Conversely, in anaerobic conditions squalene accumulates 4,5 . We have encountered an interesting situation in which squalene accumulates during cholesterologenesis in aerobic conditions.