Enables 6,7-dihydropteridine reductase activity; identical protein binding activity; and nucleotide binding activity. Involved in several processes, including L-phenylalanine catabolic process; response to glucagon; and tetrahydrobiopterin biosynthetic process. Located in cytosol and neuron projection. Biomarker of hypertension and status epilepticus. Human ortholog(s) of this gene implicated in phenylketonuria. Orthologous to human QDPR (quinoid dihydropteridine reductase). [provided by Alliance of Genome Resources, Apr 2022]