ADH1B
Encyclopedia
Alcohol dehydrogenase 1B is an enzyme
that in humans is encoded by the ADH1B gene
.
The protein encoded by this gene is a member of the alcohol dehydrogenase
family. Members of this enzyme family metabolize a wide variety of substrates, including ethanol, retinol
, other aliphatic alcohols, hydroxysteroid
s, and lipid peroxidation
products. This encoded protein, consisting of several homo- and heterodimers of alpha, beta, and gamma subunits, exhibits high activity for ethanol
oxidation and plays a major role in ethanol catabolism. Three genes encoding alpha, beta and gamma subunits are tandemly organized in a genomic segment as a gene cluster
.
The human gene is located on chromosome 4 in 4q22.
Previously ADH1B was called ADH2.
There are more genes in the family of alcohol and aldehyde dehydrogenase
genes.
These genes are now referred to as ADH1A
, ADH1C
, and ADH4
, ADH5
, ADH6
and ADH7
.
(SNP) in ADH1B is rs1229984, that changes arginine
to histidine
at residue
47.
The 'typical' variant of this has been referred to as ADH2(1) or ADH2*1 while the 'atypical' has been referred to as, e.g., ADH2(2), ADH2*2, ADH1B*47his, or ADH1B arg47-to-his.
This SNP may be related to alcohol consumption with the atypical genotype having reduced risk of alcoholism
.
Another SNP is Arg369Cys.
s taken from persons suffering from keratoconus
.
Enzyme
Enzymes are proteins that catalyze chemical reactions. In enzymatic reactions, the molecules at the beginning of the process, called substrates, are converted into different molecules, called products. Almost all chemical reactions in a biological cell need enzymes in order to occur at rates...
that in humans is encoded by the ADH1B gene
Gene
A gene is a molecular unit of heredity of a living organism. It is a name given to some stretches of DNA and RNA that code for a type of protein or for an RNA chain that has a function in the organism. Living beings depend on genes, as they specify all proteins and functional RNA chains...
.
The protein encoded by this gene is a member of the alcohol dehydrogenase
Alcohol dehydrogenase
Alcohol dehydrogenases are a group of dehydrogenase enzymes that occur in many organisms and facilitate the interconversion between alcohols and aldehydes or ketones with the reduction of nicotinamide adenine dinucleotide...
family. Members of this enzyme family metabolize a wide variety of substrates, including ethanol, retinol
Retinol
Retinol is one of the animal forms of vitamin A. It is a diterpenoid and an alcohol. It is convertible to other forms of vitamin A, and the retinyl ester derivative of the alcohol serves as the storage form of the vitamin in animals....
, other aliphatic alcohols, hydroxysteroid
Hydroxysteroid
A hydroxysteroid is a molecule derived from a steroid with a hydrogen replaced with a hydroxy group....
s, and lipid peroxidation
Lipid peroxidation
Lipid peroxidation refers to the oxidative degradation of lipids. It is the process in which free radicals "steal" electrons from the lipids in cell membranes, resulting in cell damage. This process proceeds by a free radical chain reaction mechanism...
products. This encoded protein, consisting of several homo- and heterodimers of alpha, beta, and gamma subunits, exhibits high activity for ethanol
Ethanol
Ethanol, also called ethyl alcohol, pure alcohol, grain alcohol, or drinking alcohol, is a volatile, flammable, colorless liquid. It is a psychoactive drug and one of the oldest recreational drugs. Best known as the type of alcohol found in alcoholic beverages, it is also used in thermometers, as a...
oxidation and plays a major role in ethanol catabolism. Three genes encoding alpha, beta and gamma subunits are tandemly organized in a genomic segment as a gene cluster
Gene cluster
A gene cluster is a set of two or more genes that serve to encode for the same or similar products. Because populations from a common ancestor tend to possess the same varieties of gene clusters, they are useful for tracing back recent evolutionary history...
.
The human gene is located on chromosome 4 in 4q22.
Previously ADH1B was called ADH2.
There are more genes in the family of alcohol and aldehyde dehydrogenase
Aldehyde dehydrogenase
Aldehyde dehydrogenases are a group of enzymes that catalyse the oxidation of aldehydes.- Function :Aldehyde dehydrogenase is a polymorphic enzyme responsible for the oxidation of aldehydes to carboxylic acids, which leave the liver and are metabolized by the body’s muscle and heart...
genes.
These genes are now referred to as ADH1A
ADH1A
Alcohol dehydrogenase 1A is an enzyme that in humans is encoded by the ADH1A gene.-Further reading:...
, ADH1C
ADH1C
Alcohol dehydrogenase 1C is an enzyme that in humans is encoded by the ADH1C gene.-Further reading:...
, and ADH4
ADH4
Alcohol dehydrogenase 4 is an enzyme that in humans is encoded by the ADH4 gene.-Further reading:...
, ADH5
ADH5
Alcohol dehydrogenase class-3 is an enzyme that in humans is encoded by the ADH5 gene.-Further reading:...
, ADH6
ADH6
Alcohol dehydrogenase 6 is an enzyme that in humans is encoded by the ADH6 gene.-Further reading:...
and ADH7
ADH7
Alcohol dehydrogenase class 4 mu/sigma chain is an enzyme that in humans is encoded by the ADH7 gene.-Further reading:...
.
Variants
A single nucleotide polymorphismSingle nucleotide polymorphism
A single-nucleotide polymorphism is a DNA sequence variation occurring when a single nucleotide — A, T, C or G — in the genome differs between members of a biological species or paired chromosomes in an individual...
(SNP) in ADH1B is rs1229984, that changes arginine
Arginine
Arginine is an α-amino acid. The L-form is one of the 20 most common natural amino acids. At the level of molecular genetics, in the structure of the messenger ribonucleic acid mRNA, CGU, CGC, CGA, CGG, AGA, and AGG, are the triplets of nucleotide bases or codons that codify for arginine during...
to histidine
Histidine
Histidine Histidine, an essential amino acid, has a positively charged imidazole functional group. It is one of the 22 proteinogenic amino acids. Its codons are CAU and CAC. Histidine was first isolated by German physician Albrecht Kossel in 1896. Histidine is an essential amino acid in humans...
at residue
Residue (chemistry)
In chemistry, residue is the material remaining after a distillation or an evaporation, or to a portion of a larger molecule, such as a methyl group. It may also refer to the undesired byproducts of a reaction....
47.
The 'typical' variant of this has been referred to as ADH2(1) or ADH2*1 while the 'atypical' has been referred to as, e.g., ADH2(2), ADH2*2, ADH1B*47his, or ADH1B arg47-to-his.
This SNP may be related to alcohol consumption with the atypical genotype having reduced risk of alcoholism
Alcoholism
Alcoholism is a broad term for problems with alcohol, and is generally used to mean compulsive and uncontrolled consumption of alcoholic beverages, usually to the detriment of the drinker's health, personal relationships, and social standing...
.
Another SNP is Arg369Cys.
Role in pathology
A marked decrease of ADH1B mRNA was detected in corneal fibroblastFibroblast
A fibroblast is a type of cell that synthesizes the extracellular matrix and collagen, the structural framework for animal tissues, and plays a critical role in wound healing...
s taken from persons suffering from keratoconus
Keratoconus
Keratoconus , is a degenerative disorder of the eye in which structural changes within the cornea cause it to thin and change to a more conical shape than its normal gradual curve....
.