Fatty aldehyde dehydrogenase (or Long-chain-aldehyde dehydrogenase) is an

aldehyde dehydrogenase Aldehyde dehydrogenases () are a group of enzymes that catalyse the oxidation of aldehydes. They convert aldehydes (R–C(=O)) to carboxylic acids (R–C(=O)). The oxygen comes from a water molecule. To date, nineteen ALDH genes have be ...

enzyme that in human is encoded in the ALDH3A2 gene on chromosome 17.

Aldehyde dehydrogenase Aldehyde dehydrogenases () are a group of enzymes that catalyse the oxidation of aldehydes. They convert aldehydes (R–C(=O)) to carboxylic acids (R–C(=O)). The oxygen comes from a water molecule. To date, nineteen ALDH genes have be ...

enzymes function to remove toxic

aldehydes In organic chemistry, an aldehyde () is an organic compound containing a functional group with the structure . The functional group itself (without the "R" side chain) can be referred to as an aldehyde but can also be classified as a formyl group ...

that are generated by the metabolism of alcohol and by lipid peroxidation.

Structure

The ALDH3A2 belongs to the

superfamily SUPERFAMILY is a database and search platform of structural and functional annotation for all proteins and genomes. It classifies amino acid sequences into known structural domains, especially into SCOP superfamilies. Domains are functional, str ...

and is a membrane-associated protein typically containing 485 residues. The mature protein functions as a

dimer Dimer may refer to: * Dimer (chemistry), a chemical structure formed from two similar sub-units ** Protein dimer, a protein quaternary structure ** d-dimer * Dimer model, an item in statistical mechanics, based on ''domino tiling'' * Julius Dimer ( ...

. The structure was resolved using X-ray crystallography at 2.1 Angstrom resolution. It contains an element in the C-terminal region referred to as a "gatekeeper" helix, which is adjacent to the membrane-anchored transmembrane domain and the catalytic core. The gatekeeper helix appears to control access of molecular substrates to the catalytic core and allows efficient transit between membranes and catalytic sites.

Function

ALDH3A2 catalyzes the oxidation of long-chain aliphatic aldehydes into fatty acids. It is known to act on a variety of both saturated and unsaturated aliphatic aldehydes between 6 and 24 carbons in length, as well as dihydrophytal, a 20-carbon branched chain aldehyde. It requires

NAD+ 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 ...

as a co-factor. The encoded enzyme is responsible for conversion of the

sphingosine 1-phosphate Sphingosine-1-phosphate (S1P) is a signaling sphingolipid, also known as lysosphingolipid. It is also referred to as a bioactive lipid mediator. Sphingolipids at large form a class of lipids characterized by a particular aliphatic aminoalcohol, ...

(S1P) degradation product hexadecenal to hexadecenoic acid. ALD3H2 is expressed in the human

liver The liver is a major Organ (anatomy), organ only found in vertebrates which performs many essential biological functions such as detoxification of the organism, and the Protein biosynthesis, synthesis of proteins and biochemicals necessary for ...

and has been found to localize the

microsome In cell biology, microsomes are heterogeneous vesicle-like artifacts (~20-200 nm diameter) re-formed from pieces of the endoplasmic reticulum (ER) when eukaryotic cells are broken-up in the laboratory; microsomes are not present in healthy, livin ...

fraction inside the cell. At least two

alternative splicing Alternative splicing, or alternative RNA splicing, or differential splicing, is an alternative splicing process during gene expression that allows a single gene to code for multiple proteins. In this process, particular exons of a gene may be ...

isoforms of ALDH3A2 are known to exist. The alternative transcript differs by an additional exon and anchors differently to the endoplasmic reticulum vs. the peroxisome

Clinical significance

Mutations and deletions of in the ALDH3A2 gene have been widely associated with the autosomal recessive Sjögren-Larsson syndrome, an

autosomal recessive In genetics, dominance is the phenomenon of one variant (allele) of a gene on a chromosome masking or overriding the effect of a different variant of the same gene on the other copy of the chromosome. The first variant is termed dominant and t ...

neurocutaneous disease. Multiple mutations have been found in different families, including those that molecularly disrupts the protein dimerization interface or reduces

mRNA In molecular biology, messenger ribonucleic acid (mRNA) is a single-stranded molecule of RNA that corresponds to the genetic sequence of a gene, and is read by a ribosome in the process of Protein biosynthesis, synthesizing a protein. mRNA is ...

stability. Absence or insufficiency of ALDH3A2 protein products in mutant cells are known to cause abnormal metabolism of sphingosine 1-phosphate to ether-linked

glycerolipids Lipids are a broad group of naturally-occurring molecules which includes fats, waxes, sterols, fat-soluble vitamins (such as vitamins A, D, E and K), monoglycerides, diglycerides, phospholipids, and others. The functions of lipids include s ...

and the abnormal accumulation of lipid precursors.

Structure

Function

Clinical significance

References

Further reading