Mevalonate kinase is an enzyme (specifically a kinase) that in humans is encoded by the MVK gene. Mevalonate kinases are found in a wide variety of organisms from bacteria to mammals. Mevalonate is a key intermediate, and mevalonate kinase a key early enzyme, in isoprenoid and sterol synthesis. As the second enzyme in the Mevalonate pathway, it catalyzes the phosphorylation of Mevalonic acid to produce Mevalonate-5-phosphate. A 5-10% reduction in mevalonate kinase activity is associated with the mevalonate kinase deficiency (MVD) resulting in accumulation of intermediate mevalonic acid.