Adenine is a heterobicyclic aromatic compound with a purine backbone that, as an organic nucleobase together with three other bases, forms one of the building blocks of genetic information in DNA and RNA.

In addition, adenine in the form of a nucleoside or nucleotide as NAD, FADH2 or ATP plays an important role in the metabolism, especially in the energy balance of the cells, in the mitochondria.

What is adenine?

Adenine with the chemical formula C5N5H5 consists of a heterobicyclic aromatic ring (purine skeleton) with an attached amino group (NH2). Adenine is therefore also referred to as aminopurine. It is a pale yellow solid which sublimes at 220 degrees Celsius, that is, it goes directly to the gaseous state and is poorly soluble in water.

Deposition of a deoxyribose sugar molecule results in the formation of the adenine deoxyadenosine, one of the four building blocks of the double helix DNA. The complementase is deoxythymidine, which is derived from thymidine and the deoxyribose molecule. In the case of RNA, it is a slightly modified process. Adenine becomes adenosine by attachment of a D-ribose sugar molecule. The adenosine occupies the position of the deoxyadenosine of the DNA in the RNA. The complementase is not thymine but uracil in the form of uridine.

In addition, adenosine forms the backbone of the nucleotides ATP, ADP and AMP, which play an important role in the energy balance of the cells. Adenosine also performs important functions as a cofactor in a number of enzymes, hormones, and neuromodulators such as Coenzyme A, NADPH, and NADH.

Function, effect & tasks

As part of a strand of the DNA double helix, adenosine forms the base pair adenine thymine (AT) via two hydrogen bonds with the complementary nuclein base thymine in the form of deoxythymidine. In the mostly single-stranded RNA, adenine has an analogous function, but in the formation of the complementary strand, the mRNA (messenger RNA), not thymidine is the complementary base, but uracil.

As a component of DNA and RNA, adenine is not directly involved in metabolic processes, but only serves in conjunction with the other nucleic bases of the coding of amino acid sequences for the synthesis of the corresponding proteins. Part of the energy metabolism of almost all cells, called the respiratory chain, consists essentially of a series of oxidation and reduction processes, so-called redox processes. Within the respiratory chain, the adenosine phosphorylated to adenosine triphosphate (ATP) is of central importance. ATP releases a phosphorus group and thereby becomes adenosine diphosphate (ADP) or adenosine monophosphate (AMP). Altogether it concerns an exothermic process, which over the dismantling of carbohydrates energy for the metabolism and z. B. provides for muscle work.

In this function, adenine or adenosine is directly involved in chemical reactions. An important dynamic component in the chain of redox reactions is also the electron transfer of electrons bound to hydrogen (H) or other electron carriers. Here, too, adenine and adenosine are functional constituents of enzymes or catalysts such as nicotine diamide (NAD) and others, which ultimately break down the oxidation (combustion) of hydrogen into water into many catalytically controlled individual steps and are thus available to the metabolism without causing burn damage,

Education, occurrence, properties & optimal values

Adenine exists according to the chemical formula C5N5H5, ie the basic building blocks carbon, nitrogen and hydrogen, which are abundant in nature. Rare trace elements or minerals are not needed. Accordingly, it is not a shortage of raw materials for the synthesis to be feared, but at most a problem in the body's own production process.

Since the synthesis is laborious and energy-intensive, about 90% of the body uses a different route, synthesizing adenine by recycling. In the purine metabolism, adenine is obtained as a degradation product from more complex compounds. Adenine becomes biochemically effective only as a nucleoside by addition of a molecule of deoxyribose. Adenine is thereby transformed into deoxyadenosine. With further addition of one to three phosphate residues, the deoxyadenosine becomes a nucleotide called adenosine monophosphate (AMP), cyclic adenosine monophosphate (cAMP), adenosine diphosphate (ADP) or adenosine triphosphate (ATP).

Given the diverse roles of adenine and its biochemically active manifestations in an environment that meets dynamically changing requirements, and free adenine does not occur in the systemic circulation, any level of adenine can not be measured. It is only by observing and measuring certain metabolic processes that indirect conclusions can be drawn about an intact purine metabolism.

Diseases & Disorders

The most well-known - in fact rare - metabolic disorder associated with the body's formation of adenine and its bioactive forms is Lesch-Nyhan syndrome. It is a genetic defect on the x chromosome. The gene mutation leads to a complete lack of hypoxanthine-guanine phosphoribosyltransferase (HGPRT).

The absence of HGPRT leads to a disturbance in the purine metabolism, so that the normally occurring recycling of the purine bases hypoxanthine and guanine is omitted. Instead, the body is forced to produce adenine via neosynthesis on an ongoing basis. This leads to an excessive amount of uric acid and precipitation of uric acid crystals, which can cause gout or the formation of urinary stones in the joints. In addition, neonates typically develop mental development deficits and increased autoaggression.

Another rare hereditary disease is Huntington's disease. Here is a gene defect on chromosome 4. Normally, the base sequence cytosine-adenine-guanine is found there in a particular gene with 10 to 30 repetitions. If it is due to a gene mutation to more than 36 of these so-called triplet repetitions, the hereditary disease Huntington's disease occurs. In the course of the disease, there are motor problems and nerve damage that are not curable.

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