Carboxy-lyases, also known as decarboxylases, are
carbon–carbon lyases
In biochemistry, a lyase is an enzyme that catalyzes the breaking (an elimination reaction) of various chemical bonds by means other than hydrolysis (a substitution reaction) and oxidation, often forming a new double bond or a new ring structu ...
that add or remove a
carboxyl
In organic chemistry, a carboxylic acid is an organic acid that contains a carboxyl group () attached to an R-group. The general formula of a carboxylic acid is or , with R referring to the alkyl, alkenyl, aryl, or other group. Carboxylic ...
group from
organic compound
In chemistry, organic compounds are generally any chemical compounds that contain carbon-hydrogen or carbon-carbon bonds. Due to carbon's ability to catenate (form chains with other carbon atoms), millions of organic compounds are known. Th ...
s. These
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 ...
s catalyze the decarboxylation of amino acids, beta-keto acids and alpha-keto acids.
Classification and nomenclature
Carboxy-lyases are categorized under
EC number 4.1.1.
Usually, they are named after the substrate whose
decarboxylation
Decarboxylation is a chemical reaction that removes a carboxyl group and releases carbon dioxide (CO2). Usually, decarboxylation refers to a reaction of carboxylic acids, removing a carbon atom from a carbon chain. The reverse process, which is ...
they
catalyze, for example
pyruvate decarboxylase
Pyruvate decarboxylase is an enzyme () that catalyses the decarboxylation of pyruvic acid to acetaldehyde. It is also called 2-oxo-acid carboxylase, alpha-ketoacid carboxylase, and pyruvic decarboxylase. In anaerobic conditions, this enzyme is ...
catalyzes the decarboxylation of
pyruvate
Pyruvic acid (CH3COCOOH) is the simplest of the alpha-keto acids, with a carboxylic acid and a ketone functional group. Pyruvate, the conjugate base, CH3COCOO−, is an intermediate in several metabolic pathways throughout the cell.
Pyruvic a ...
.
Examples
*
Aromatic-L-amino-acid decarboxylase
*
Glutamate decarboxylase
*
Histidine decarboxylase
The enzyme histidine decarboxylase (, HDC) is transcribed on chromosome 15, region 21.2, and catalyzes the decarboxylation of histidine to form histamine. In mammals, histamine is an important biogenic amine with regulatory roles in neurotransmi ...
*
Ornithine decarboxylase
The enzyme ornithine decarboxylase (, ODC) catalyzes the decarboxylation of ornithine (a product of the urea cycle) to form putrescine. This reaction is the committed step in polyamine synthesis. In humans, this protein has 461 amino acids and f ...
*
Phosphoenolpyruvate carboxylase
*
Pyruvate decarboxylase
Pyruvate decarboxylase is an enzyme () that catalyses the decarboxylation of pyruvic acid to acetaldehyde. It is also called 2-oxo-acid carboxylase, alpha-ketoacid carboxylase, and pyruvic decarboxylase. In anaerobic conditions, this enzyme is ...
*
RuBisCO – the only carboxylase that leads to a net fixation of carbon dioxide
*
Uridine monophosphate synthetase
*
Uroporphyrinogen III decarboxylase
Uroporphyrinogen III decarboxylase (uroporphyrinogen decarboxylase, or UROD) is an enzyme () that in humans is encoded by the ''UROD'' gene.
Function
Uroporphyrinogen III decarboxylase is a homodimeric enzyme () that catalyzes the fifth step i ...
* enoyl-CoA carboxylases/reductases (ECRs)
See also
*
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 ...
s
*
Lyase
In biochemistry, a lyase is an enzyme that catalyzes the breaking (an elimination reaction) of various chemical bonds by means other than hydrolysis (a substitution reaction) and oxidation, often forming a new double bond or a new ring structu ...
s
*
List of EC numbers of enzymes belonging to category EC 4.1
References
External links
*
*
{{4.1-enzyme-stub