– L-Dihydroorotic acid, also known as (S)-4,5-dihydroorotate or dihydro-L-orotate, belongs to the class of organic compounds known as alpha amino acids and derivatives. Within the cell, L-dihydroorotic acid is primarily located in the cytoplasm and mitochondria. L-Dihydroorotic acid exists in all eukaryotes, ranging from yeast to humans. L-Dihydroorotic acid participates in a number of enzymatic reactions. In particular, L-Dihydroorotic acid can be biosynthesized from ureidosuccinic acid; which is catalyzed by the enzyme cad protein. In addition, L-Dihydroorotic acid and quinone can be converted into orotic acid; which is mediated by the enzyme dihydroorotate dehydrogenase (quinone), mitochondrial. In humans, L-dihydroorotic acid is involved in the pyrimidine metabolism pathway. L-Dihydroorotic acid is also involved in several metabolic disorders, some of which include UMP synthase deficiency (orotic aciduria), the mngie (mitochondrial neurogastrointestinal encephalopathy) pathway, Beta ureidopropionase deficiency, and dihydropyrimidinase deficiency.