In enzymology, a diiodophenylpyruvate reductase () is an enzyme that catalyzes the chemical reaction
Thus, the two substrates of this enzyme are 3-(3,5-diiodo-4-hydroxyphenyl)lactate and NAD<sup>+</sup>, whereas its 3 products are 3-(3,5-diiodo-4-hydroxyphenyl)pyruvate, NADH, and H<sup>+</sup>.
This enzyme belongs to the family of oxidoreductases, specifically those acting on the CH-OH group of donor with NAD<sup>+</sup> or NADP<sup>+</sup> as acceptor. The systematic name of this enzyme class is 3-(3,5-diiodo-4-hydroxyphenyl)lactate:NAD<sup>+</sup> oxidoreductase. Other names in common use include aromatic alpha-keto acid, KAR, and 2-oxo acid reductase.
In 2025, this enzyme was found to be identical to , (S)-malate dehydrogenase.