Despite the presence of the "de novo" pathway, the salvage reactions are essential in humans; a lack of niacin in the diet causes the vitamin deficiency disease pellagra.
This gene encodes an enzyme - dihydroorotate dehydrogenase - which catalyses the ubiquinone-mediated oxidation of dihydroorotate to orotate, the fourth enzymatic step in "de novo" pyrimidine biosynthesis.
This effect may have therapeutical relevance given that the schistosome, as the taenia and the echinococcus (other praziquantel sensitive parasites), is unable to synthesize purines such as adenosine "de novo".