Dihydrobiopterin reductase

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Dihydrobiopterin reductase is an enzyme that catalyzes the reversible formation of tetrahydrobiopterin from dihydrobiopterine using NADPH. A deficiency of this enzyme can result in malignant hyperphenylalaninemia.[1]

Dihydrobiopterin is a compound produced in the synthesis of dopamine, norepinephrine and epinephrine through production of the intermediate L-3,4-dihydroxyphenylalanine, also known as L-DOPA. Phenylalanine is converted into dopa using tetrahydrobiopterin releasing dihydrobiopterin and water, which is then converted back into tetrahydrobiopterin using the NADPH-dependent enzyme dihydrobiopterin reductase. This enzyme is sometimes defective in patients with phenylketonuria, and is treated in the same fashion, with tyrosine supplements and a controlled diet which is lacking in phenylalanine.[2]

See also[edit]


  1. ^ "Dihydropteridine reductase". 
  2. ^ Pawlina, Wojciech; Ross, Michael W. (2006). Histology: a text and atlas: with correlated cell and molecular biology. Philadelphia: Lippincott Wiliams & Wilkins. ISBN 0-7817-5056-3.