3-hydroxyisobutyrate dehydrogenase

In enzymology, a 3-hydroxyisobutyrate dehydrogenase (EC 1.1.1.31) also known as β-hydroxyisobutyrate dehydrogenase or 3-hydroxyisobutyrate dehydrogenase, mitochondrial (HIBADH) is an enzyme that in humans is encoded by the HIBADH gene.

3-Hydroxyisobutyrate dehydrogenase catalyzes the chemical reaction:

3-hydroxy-2-methylpropanoate + NAD⁺ ${\displaystyle \rightleftharpoons }$ 2-methyl-3-oxopropanoate + NADH + H⁺

Thus, the two substrates of this enzyme are 3-hydroxy-2-methylpropanoate and NAD⁺, whereas its 3 products are 2-methyl-3-oxopropanoate, NADH, and H⁺.

This enzyme belongs to the family of oxidoreductases, specifically those acting on the CH-OH group of donor with NAD⁺ or NADP⁺ as acceptor. The systematic name of this enzyme class is 3-hydroxy-2-methylpropanoate:NAD⁺ oxidoreductase. This enzyme participates in valine, leucine and isoleucine degradation.