nad-dependent methylenetetrahydrofolate dehydrogenase 2-like protein (mthfd2l), also known as bifunctional methylenetetrahydrofolate dehydrogenase/cyclohydrolase 2, is an enzyme that in humans is encoded by the "mthfd2l" gene on chromosome 4. this enzyme localizes to the inner mitochondrial membrane, where it performs the nadp+-dependent dehydrogenase/cyclohydrolase activity as part of the mitochondrial pathway to convert folate to formate.