The mevalonate pathway, also known as the isoprenoid pathway, plays an essential role in creating the chemicals needed for many plants to function. This pathway, combined with the MEP/DOXP pathway give many plants their scents, such as cinnamon and ginger, and are responsible for the red colour in tomatoes. The pathway begins with acetyl-CoA, having come from the glycolysis pathway. Acetyl-CoA immediately becomes acetoacetyl-CoA through the enzyme acetyl-CoA acetyltransferase 1/2. Combined, acetoacetyl-CoA and acetyl-CoA react with hydroxymethylglutaryl-CoA synthase to create 3-hydroxy-3methylglutaryl-CoA. From here, this compound is catalyzed by 3-hydroxy-3-methylglutaryl-coenzyme A reductase 1 and becomes (R)-mevalonate. Mevalonate is paired with mevalonate kinase to produce mevalonic acid-5P. In turn, mevalonic acid-5P reacts with phosphomevalonate kinase, and entering the peroxisome and becoming (R)-mevalonic acid-5-pyrophosphate. Remaining in the peroxisome, diphosphomevalonate decarboxylase MVD1 is used alongside (R)-mevalonic acid-5-pyrophosphate to create isopentenyl pyrophosphate, bringing the pathway into the chloroplast. Dimethylallylpyrophosphate is produced after isopentenyl pyrophosphate and isopentenyl diphosphate delta-isomerase II team up to catalyze it. Dimethylallylpyrophosphate then joins forces with isopentenyl again, this time adding geranylgeranyl pyrophosphate synthase 6 and moving into the mitochondria to produce geranyl-PP. This is followed by monoterpenoid biosynthesis.

Mevalonate Pathway References