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^[5] that in humans is encoded by the HIBADH gene.^[6]

Quick Facts HIBADH, Available structures ...

HIBADH
Available structures PDB Ortholog search: PDBe RCSB List of PDB id codes 2GF2, 2I9P
Identifiers
Aliases	HIBADH, Hibadh, 6430402H10Rik, AI265272, NS5ATP1, 3-hydroxyisobutyrate dehydrogenase
External IDs	OMIM: 608475; MGI: 1889802; HomoloGene: 15088; GeneCards: HIBADH; OMA:HIBADH - orthologs
EC number	1.1.1.31
Gene location (Human) Chr. Chromosome 7 (human)[1] Band 7p15.2 Start 27,525,442 bp[1] End 27,662,883 bp[1]
Gene location (Mouse) Chr. Chromosome 6 (mouse)[2] Band 6|6 B3 Start 52,523,213 bp[2] End 52,617,374 bp[2]
RNA expression pattern Bgee Human Mouse (ortholog) Top expressed in renal medulla kidney left adrenal gland quadriceps femoris muscle vastus lateralis muscle deltoid muscle biceps brachii right ventricle right lobe of liver tibialis anterior muscle Top expressed in brown adipose tissue epithelium of stomach proximal tubule interventricular septum lacrimal gland myocardium of ventricle left lobe of liver right ventricle digastric muscle white adipose tissue More reference expression data BioGPS More reference expression data
Gene ontology Molecular function 3-hydroxyisobutyrate dehydrogenase activity oxidoreductase activity NAD binding phosphogluconate dehydrogenase (decarboxylating) activity NADP binding oxidoreductase activity, acting on the CH-OH group of donors, NAD or NADP as acceptor Cellular component mitochondrial matrix mitochondrion Biological process valine catabolic process branched-chain amino acid catabolic process Sources:Amigo / QuickGO
Orthologs Species Human Mouse Entrez 11112 58875 Ensembl ENSG00000106049 ENSMUSG00000029776 UniProt P31937 Q99L13 RefSeq (mRNA) NM_152740 NM_145567 RefSeq (protein) NP_689953 NP_663542 Location (UCSC) Chr 7: 27.53 – 27.66 Mb Chr 6: 52.52 – 52.62 Mb PubMed search [3] [4]
Wikidata
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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.

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]

As of late 2007, five structures have been solved for this class of enzymes, with PDB accession codes 1WP4, 2CVZ, 2GF2, 2H78, and 2I9P.