In
enzymology, a 3-hydroxyisobutyrate dehydrogenase () also known as β-hydroxyisobutyrate dehydrogenase or 3-hydroxyisobutyrate dehydrogenase, mitochondrial (HIBADH) is an
enzyme
Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrates, and the enzyme converts the substrates into different molecules known as products ...
that in humans is encoded by the ''HIBADH''
gene
In biology, the word gene (from , ; "... Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a b ...
.
3-Hydroxyisobutyrate dehydrogenase
catalyzes the
chemical reaction
A chemical reaction is a process that leads to the IUPAC nomenclature for organic transformations, chemical transformation of one set of chemical substances to another. Classically, chemical reactions encompass changes that only involve the pos ...
:
:3-hydroxy-2-methylpropanoate + NAD
+ 2-methyl-3-oxopropanoate + NADH + H
+
Thus, the two
substrates of this enzyme are
3-hydroxy-2-methylpropanoate and
NAD+, whereas its 3
products
Product may refer to:
Business
* Product (business), an item that serves as a solution to a specific consumer problem.
* Product (project management), a deliverable or set of deliverables that contribute to a business solution
Mathematics
* Produ ...
are
2-methyl-3-oxopropanoate,
NADH
Nicotinamide adenine dinucleotide (NAD) is a coenzyme central to metabolism. Found in all living cells, NAD is called a dinucleotide because it consists of two nucleotides joined through their phosphate groups. One nucleotide contains an aden ...
, and
H+.
This enzyme belongs to the family of
oxidoreductase
In biochemistry, an oxidoreductase is an enzyme that catalyzes the transfer of electrons from one molecule, the reductant, also called the electron donor, to another, the oxidant, also called the electron acceptor. This group of enzymes usually u ...
s, specifically those acting on the CH-OH group of donor with NAD
+ or NADP
+ as acceptor. The
systematic name A systematic name is a name given in a systematic way to one unique group, organism, object or chemical substance, out of a specific population or collection. Systematic names are usually part of a nomenclature.
A semisystematic name or semitrivial ...
of this enzyme class is 3-hydroxy-2-methylpropanoate:NAD
+ oxidoreductase. This enzyme participates in
valine, leucine and isoleucine degradation
A branched-chain amino acid (BCAA) is an amino acid having an aliphatic side-chain with a branch (a central carbon atom bound to three or more carbon atoms). Among the proteinogenic amino acids, there are three BCAAs: leucine, isoleucine, and va ...
.
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
A structure is an arrangement and organization of interrelated elements in a material object or system, or the object or system so organized. Material structures include man-made objects such as buildings and machines and natural objects such as ...
have been solved for this class of enzymes, with
PDB accession codes , , , , and .
References
Further reading
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External links
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PDBe-KBprovides an overview of all the structure information available in the PDB for Human 3-hydroxyisobutyrate dehydrogenase, mitochondrial
EC 1.1.1
NADH-dependent enzymes
Enzymes of known structure
Human proteins
{{1.1.1-enzyme-stub