In
enzymology, a 3-hydroxyisobutyrate dehydrogenase (
EC1.1.1.31) also known as β-hydroxyisobutyrate dehydrogenase or 3-hydroxyisobutyrate dehydrogenase, mitochondrial (HIBADH) is an
enzyme[5] that in humans is encoded by the HIBADHgene.[6]
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.
Function
3-hydroxyisobutyrate dehydrogenase is a tetrameric mitochondrial enzyme that catalyzes the NAD+-dependent, reversible oxidation of 3-hydroxyisobutyrate, an intermediate of valine catabolism, to methylmalonate semialdehyde.[6]
Structural studies
As of late 2007, five
structures have been solved for this class of enzymes, with
PDB accession codes
1WP4,
2CVZ,
2GF2,
2H78, and
2I9P.