Trans-2-enoyl-CoA reductase, mitochondrial is an

enzyme An enzyme () is a protein that acts as a biological catalyst by accelerating chemical reactions. The molecules upon which enzymes may act are called substrate (chemistry), substrates, and the enzyme converts the substrates into different mol ...

that in humans is encoded by the ''MECR''

gene In biology, the word gene has two meanings. The Mendelian gene is a basic unit of heredity. The molecular gene is a sequence of nucleotides in DNA that is transcribed to produce a functional RNA. There are two types of molecular genes: protei ...

Structure

The ''MECR'' gene is located on the 1st chromosome, with its specific location being 1p35.3. The gene contains 15

exon An exon is any part of a gene that will form a part of the final mature RNA produced by that gene after introns have been removed by RNA splicing. The term ''exon'' refers to both the DNA sequence within a gene and to the corresponding sequence ...

s. ''MECR'' encodes a 21.2 kDa protein that is composed of 189

amino acid Amino acids are organic compounds that contain both amino and carboxylic acid functional groups. Although over 500 amino acids exist in nature, by far the most important are the 22 α-amino acids incorporated into proteins. Only these 22 a ...

s; 10

peptide Peptides are short chains of amino acids linked by peptide bonds. A polypeptide is a longer, continuous, unbranched peptide chain. Polypeptides that have a molecular mass of 10,000 Da or more are called proteins. Chains of fewer than twenty am ...

s have been observed through

mass spectrometry Mass spectrometry (MS) is an analytical technique that is used to measure the mass-to-charge ratio of ions. The results are presented as a ''mass spectrum'', a plot of intensity as a function of the mass-to-charge ratio. Mass spectrometry is used ...

data.]

Function

The protein encoded by ''MECR'' is an

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 ut ...

that catalyzes the last step in

mitochondrial fatty acid synthesis In biochemistry, fatty acid synthesis is the creation of fatty acids from acetyl-CoA and NADPH through the action of enzymes. Two '' de novo'' fatty acid syntheses can be distinguished: cytosolic fatty acid synthesis (FAS/FASI) and mitochondrial ...

(mtFAS). MECR reduces trans-2-enoyl- ACP to acyl-ACP using

NADPH Nicotinamide adenine dinucleotide phosphate, abbreviated NADP or, in older notation, TPN (triphosphopyridine nucleotide), is a cofactor used in anabolic reactions, such as the Calvin cycle and lipid and nucleic acid syntheses, which require N ...

as a

reducing agent In chemistry, a reducing agent (also known as a reductant, reducer, or electron donor) is a chemical species that "donates" an electron to an (called the , , , or ). Examples of substances that are common reducing agents include hydrogen, carbon ...

. The resulting saturated acyl-ACP can then re-enter the mtFAS cycle for further chain elongation. The reaction can be summarized by the following equation: trans-2-enoyl-ACP + NADPH + H⁺ → Acyl-ACP + NADP⁺ The mtFAS pathway is essential for producing octanoyl- ACP that is used to synthesize

lipoic acid Lipoic acid (LA), also known as α-lipoic acid, alpha-lipoic acid (ALA) and thioctic acid, is an organosulfur compound derived from caprylic acid (octanoic acid). ALA, which is made in animals normally, is essential for aerobic metabolism. It i ...

, which is essential for aerobic metabolism. A

Purkinje cell Purkinje cells or Purkinje neurons, named for Czech physiologist Jan Evangelista Purkyně who identified them in 1837, are a unique type of prominent, large neuron located in the Cerebellum, cerebellar Cortex (anatomy), cortex of the brain. Wi ...

specific

knock out A knockout (abbreviated to KO or K.O.) is a fight-ending, winning criterion in several Contact sports, full-contact combat sports, such as boxing, kickboxing, Muay Thai, mixed martial arts, karate, some forms of World Taekwondo Federation#Sparri ...

of the ''Mecr'' gene in mice leads to

neurodegeneration A neurodegenerative disease is caused by the progressive loss of neurons, in the process known as neurodegeneration. Neuronal damage may also ultimately result in their cell death, death. Neurodegenerative diseases include amyotrophic lateral sc ...

Clinical significance

Genetic mutations to ''MECR'' have been suggested to cause MEPAN Syndrome, a neurometabolic disorder in humans that involves disruptions in the pathway involved in mitochondrial fatty acid synthesis (mtFAS). MEPAN patients were found to harbor recessive mutations in ''MECR'', and typically present with childhood-onset

dystonia Dystonia is a neurology, neurological Hyperkinesia, hyperkinetic Movement disorders, movement disorder in which sustained or repetitive muscle contractions occur involuntarily, resulting in twisting and repetitive movements or abnormal fixed po ...

optic atrophy Optic neuropathy is damage to the optic nerve from any cause. The optic nerve is a bundle of millions of fibers in the retina that sends visual signals to the brain. Damage and death of these nerve cells, or neurons, leads to characteristic featu ...

, and

basal ganglia The basal ganglia (BG) or basal nuclei are a group of subcortical Nucleus (neuroanatomy), nuclei found in the brains of vertebrates. In humans and other primates, differences exist, primarily in the division of the globus pallidus into externa ...

signal abnormalities on

MRI Magnetic resonance imaging (MRI) is a medical imaging technique used in radiology to generate pictures of the anatomy and the physiological processes inside the body. MRI scanners use strong magnetic fields, magnetic field gradients, and rad ...

Structure

Function

Clinical significance

See also

References

Further reading