Adénine

Definition

The adénine is a chemical molecule of empirical formula C₅H₅N₅, pertaining to the family of the Purine S. Its name chemical is 1,6-dihydro-6-iminopurine , one can also call it 6-aminopurine or amino-6-purin . The adénine is a molecule Hétérocyclique, i.e. it contains Hétérocycle S. By definition, a heterocycle is a cycle which is not exclusively made up of Carbone. The adénine has several atoms indeed associated nitrogen cycles some with carbon atoms.

The adénine is also a nitrogenized Base entering the constitution of the Nucléotide S, components basic (or Monomère S) of the nucleic acid .

Finally, the adénine is also regarded by certain works as being the vitamin B4. By definition, a Vitamine is a substance which one does not synthesize by ourself and thus that one must adapt in our food. However, the Carence S associated with the vitamin B4 are rare because practically all that we introduce contains of the adénine, and mainly in the Brewers' yeast, the Pain and the The. Very rare deficiencies can be caused by certain Médicament S like the Sulfamidé S. For this reason, some affirm that it is not a question of a vitamin to the clean direction of the term.

Prebiotic origin

It was proven that the adénine could conceive starting from five molecules (thus a Pentamère) of hydrocyanic acid of empirical formula HCN. Indeed, of the experiments of prebiotic biochemistry show that hydrocyanic acid in the liquid state spontaneously will allow the appearance of a negligible quantity of adénine.

Characteristics

Complementarity

Adénine is said that it is a nitrogenized base complementary . Indeed, this complementarity is observed mainly in the nucleic acid where the adénine binds by two hydrogen bonds with the Thymine in the DNA or uracil in the ARN. The Thymine and uracil are other bases nitrogenized of the family of the Pyrimidine S.

Physico-chemical characteristics

Point melting

The melting point of the adénine ranges between 360 and 365 °C. It is about a relatively high melting point for a made up organics. That is explained inter alia by the space organization of the molecules the ones compared to the others in the medium. In fact, these Molécule S has acceptors fields of hydrogen bonds and donors of hydrogen bonds, they thus take part in several of these connections. The molecules of adénine are thus associated in “network”, reserves strongly the ones with the others by these hydrogen bonds.

The well the Molécule S are retained units, the more it will be necessary to provide energy (for example: Heat) to dissociate them and thus to pass from the solid phase to the liquid phase .

Atomic mass

The Atomic mass of the adénine is of 135.128 daltons. One obtains this atomic mass by adding the mass with each Atome present in the Molécule. The respective masses of each atom are goods known and are usually given in the periodic Tableau of the elements.

Utilities

The adénine is a compound which has several utilities. During the evolution, it seems that the adénine was a compound “appreciated” by the living organisms from its effectiveness. It thus proves that during the diversification of the immense quantity of chemical reactions being held in the living organisms, the adénine was found to play several key parts. Here thus the principal compounds in which the adénine takes share.

Nucleotide

The adénine enters the composition of the Nucléotide S. The latter are inter alia the Monomère S, or raw materials, of the nucleic acid . The nucleotide containing of the adénine and that one finds in the DNA names Désoxyadénosine monophosphate while that composing ARN names Adénosine monophosphate.

In nucleotides, the adénine binds to a Pentose, it (Désoxyribose in the case of the DNA or Ribose in the case of the ARN) which itself binds to a grouping phosphates in position 5 of sugar. In these Nucleotide S, the adénine is called the nitrogenized Base and it determines the characteristics specific to nucleotide. They are not hydrophobic contrary to the substituted nitrogenized bases.

Adenosine triphosphate

The Adenosine triphosphate or ATP, is also a Nucléotide, the only difference between this one and those present in the nucleic acid resides at the level of the number of groupings phosphates attached to the Nucléoside (a nucleoside is a nucleotide without grouping phosphates). In fact, as their names indicate it, adenosine triphosphate has three groupings phosphates and the Adénosine monophosphate has only one of them.

The ATP is a high molecule in energy, it is thus used as energy currency of exchange. It is present everywhere in the organization and is possibly hydrolized to provide the energy necessary to a reaction requiring an energy contribution which one describes as dependant reaction ATP like the muscular contractions, certain ionic exchanges, certain enzymatic reactions, the activation of several proteins, the migration of the intracellular blisters, and well of others.

ATP is one of the products of the Catabolisme of the nutrients (mainly sugars as the Glucose) which one adapts while eating. ATP is formed mainly in the Mitochondrie S during the process of the Chaîne of transport of electron, a stage among others appearing in the process of disintegration of sugars.

Cyclic adenosine monophosphate

The cyclic Adenosine monophosphate or AMPc is the processed product of ATP by a named Enzyme Adénylyl cyclase, which resides in the cellular membranes. AMPc is a Second messenger playing a cellular big role of indication in a process named Transduction of signals.

AMPc plays also a part of regulation of the expression of some Gène S.

At Dictyostelium discoideum, a Ameba, the cyclic Adénosine monophosphate makes it possible to announce to an individual the proximity of another member of sound Espèce. Indeed, under conditions where the nutrients have suddenly missed in the medium, all the individuals of this species tend to gather to form a larger holistic entity able to better support the constraints of the environment. This regrouping takes place by chemotropism cyclic adenosine monophosphate, i.e. each individual emits a Pseudopode (cytoplasmic arm) in the direction of a gradient of detected AMPc, therefore an area with high content of AMPc. These Amibe S secretes of AMPc in their turn to attract their congeneric towards them. There exist also average employees by Dictyostelium discoideum so that each individual does not emit AMPc in order to disorientate itself.

Other molecules containing of the adénine

The Nicotinamide adénine dinucléotide or NAD⁺ , a derivative of the Niacine as well as the Flavin adénine dinucléotide or FAD , a derivative of the Riboflavin, are important Coenzyme S in the oxydative ways. These Molécule S is reduced in the respective forms of NADH and FADH₂ at the time of the various stages of oxidation of the Catabolisme of the Sucre S. They are reduced by accepting atoms hydrogen.

Other nitrogenized bases

Of the family of the Purin S:

# Guanine

# Hypoxanthine

Of the family of the Pyrimidin S:

# Cytosine

# Thymine

# Uracil

Random links: