Mevalonic acid

Mevalonic acid (also known as mevalonate) is a key organic compound in biochemistry. The name is derived from the plant mevalonate from which it was first isolated. It is a precursor in the biosynthetic pathway known as the mevalonate pathway that produces terpenes and steroids.

Structure and properties

Mevalonic acid is a six-carbon compound with a carboxyl group (COOH) and two hydroxyl groups (OH). Its molecular formula is C6H12O4. It is a white, crystalline solid at room temperature.

Biosynthesis

Mevalonic acid is synthesized from acetyl-CoA in three steps. First, two molecules of acetyl-CoA condense to form acetoacetyl-CoA. This is followed by the addition of another acetyl-CoA to form 3-hydroxy-3-methylglutaryl-CoA (HMG-CoA). HMG-CoA is then reduced to mevalonic acid by the enzyme HMG-CoA reductase, a step that is regulated by feedback inhibition.

Role in isoprenoid biosynthesis

Mevalonic acid is the precursor for the biosynthesis of isoprenoids, a large and diverse class of molecules that includes cholesterol, steroid hormones, vitamin D, and many others. The conversion of mevalonic acid to isoprenoids involves several steps, including the formation of isopentenyl pyrophosphate (IPP) and dimethylallyl pyrophosphate (DMAPP), which are the building blocks of all isoprenoids.

Clinical significance

In humans, the production of mevalonic acid is an important cellular process. Defects in this pathway can lead to a variety of diseases, including hypercholesterolemia and mevalonate kinase deficiency. In addition, inhibitors of HMG-CoA reductase, such as the statins, are widely used to lower cholesterol levels.

See also

• HMG-CoA reductase
• Mevalonate pathway
• Isoprenoid
• Statins