3-hydroxyisobutyrate dehydrogenase

In enzymology, a 3-hydroxyisobutyrate dehydrogenase () 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:

The two substrates of this enzyme are 3-hydroxyisobutyric acid and oxidised nicotinamide adenine dinucleotide (NAD⁺). Its products are methylmalonic acid semialdehyde, reduced NADH, and a proton.

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.

Structural studies

As of late 2007, five structures have been solved for this class of enzymes, with PDB accession codes , , , , and .

References

Further reading

External links

• PDBe-KB provides an overview of all the structure information available in the PDB for Human 3-hydroxyisobutyrate dehydrogenase, mitochondrial