ACADSB is a human

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 ba ...

that encodes short/branched chain specific acyl-CoA dehydrogenase (SBCAD), 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. A ...

in the acyl CoA dehydrogenase family. It can cause short/branched-chain acyl-CoA dehydrogenase deficiency.

Structure

The human ACADSB gene is located on chromosome 10; its exact localization has been identified as 10q25-q26. The

open reading frame In molecular biology, open reading frames (ORFs) are defined as spans of DNA sequence between the start and stop codons. Usually, this is considered within a studied region of a prokaryotic DNA sequence, where only one of the six possible readin ...

(ORF) encodes a precursor protein that contains 431

amino acids Amino acids are organic compounds that contain both amino and carboxylic acid functional groups. Although hundreds of amino acids exist in nature, by far the most important are the alpha-amino acids, which comprise proteins. Only 22 alpha am ...

; post-translational processing results in a mature protein with 399 amino acids. The cDNA is significantly similar to the

cDNA In genetics, complementary DNA (cDNA) is DNA synthesized from a single-stranded RNA (e.g., messenger RNA (mRNA) or microRNA (miRNA)) template in a reaction catalyzed by the enzyme reverse transcriptase. cDNA is often used to express a speci ...

of other members of the acyl-CoA dehydrogenase family; its structure is closest to that of short chain acyl-CoA dehydrogenase. The structure of the catalytic pocket has also been studied; position 104 at the bottom of the substrate-binding pocket has been identified as important in determining the length of the primary carbon chain that can be accommodated. Altering residues at positions 105 and 177 have been demonstrated to affect the rate of the

dehydrogenation In chemistry, dehydrogenation is a chemical reaction that involves the removal of hydrogen, usually from an organic molecule. It is the reverse of hydrogenation. Dehydrogenation is important, both as a useful reaction and a serious problem. At ...

reactions.

Function

Short/branched chain acyl-CoA dehydrogenase (ACADSB) is a member of the acyl-CoA dehydrogenase family of enzymes that catalyze the dehydrogenation of acyl-CoA derivatives in the metabolism of fatty acids or branch chained amino acids. Substrate specificity is the primary characteristic used to define members of this gene family. The ACADSB gene product has the greatest activity towards the short branched chain acyl-CoA derivative, (S)-2-methylbutyryl-CoA, but also reacts significantly with other 2-methyl branched chain substrates and with short straight chain acyl- CoAs. The encoded protein is also involved in L- leucine catabolism.

Clinical significance

Mutations in the ACADSB gene have been associated with 2-Methylbutyryl-CoA dehydrogenase deficiency (SBCADD, also known as MBD) deficiency, 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 ...

metabolic disorder A metabolic disorder is a disorder that negatively alters the body's processing and distribution of macronutrients, such as proteins, fats, and carbohydrates. Metabolic disorders can happen when abnormal chemical reactions in the body alter the ...

of impaired

isoleucine Isoleucine (symbol Ile or I) is an α-amino acid that is used in the biosynthesis of proteins. It contains an α-amino group (which is in the protonated −NH form under biological conditions), an α-carboxylic acid group (which is in the deprot ...

degradation. Many mutations across the gene's 10 exons have been identified, with the mutations causing exon skipping and other transcriptional and translational errors. The disorder may be detected by MS/MS-based routine newborn screening due to the heightened presence of 2-methylbutyrylcarnitine in tissue samples. The disorder may also be identified using urinary organic acid analysis, by detecting the presence of 2-methylbutyryl glycinuria. While many individuals with a mutation in this gene may be asymptomatic, some patients have been reported to have symptoms in early infancy. Infants may experience

apneic Apnea, BrE: apnoea, is the temporal cessation of breathing. During apnea, there is no movement of the muscles of inhalation, and the volume of the lungs initially remains unchanged. Depending on how blocked the airways are ( patency), there may ...

episodes, generalized

muscle atrophy Muscle atrophy is the loss of skeletal muscle mass. It can be caused by immobility, aging, malnutrition, medications, or a wide range of injuries or diseases that impact the musculoskeletal or nervous system. Muscle atrophy leads to muscle weakness ...

hypotonia Hypotonia is a state of low muscle tone (the amount of tension or resistance to stretch in a muscle), often involving reduced muscle strength. Hypotonia is not a specific medical disorder, but a potential manifestation of many different diseases a ...

lethargy Lethargy is a state of tiredness, sleepiness, weariness, fatigue, sluggishness or lack of energy. It can be accompanied by depression, decreased motivation, or apathy. Lethargy can be a normal response to inadequate sleep, overexertion, overwo ...

seizures An epileptic seizure, informally known as a seizure, is a period of symptoms due to abnormally excessive or neural oscillation, synchronous neuronal activity in the brain. Outward effects vary from uncontrolled shaking movements involving much o ...

, and delayed motor development. Patients may also experience metabolic symptoms such as

hypothermia Hypothermia is defined as a body core temperature below in humans. Symptoms depend on the temperature. In mild hypothermia, there is shivering and mental confusion. In moderate hypothermia, shivering stops and confusion increases. In severe h ...

and

hypoglycemia Hypoglycemia, also called low blood sugar, is a fall in blood sugar to levels below normal, typically below 70 mg/dL (3.9 mmol/L). Whipple's triad is used to properly identify hypoglycemic episodes. It is defined as blood glucose belo ...

. Finally, genetic polymorphisms of the ACADSB gene may also be involved in the development of

hypertension Hypertension (HTN or HT), also known as high blood pressure (HBP), is a long-term medical condition in which the blood pressure in the arteries is persistently elevated. High blood pressure usually does not cause symptoms. Long-term high bl ...

in the Japanese population.

References

External links

* * EC 1.3.99 Genes on human chromosome 10 {{oxidoreductase-stub