Denaturation

In biochemistry, the denaturation is the process by which a Macromolécule biological, Nucleic acid or Protéine, loses its three-dimensional conformation normal. This three-dimensional conformation is generally necessary so that the biological macromolecules can fill to them function.

Denaturation of the DNA

The DNA known as is denatured when the two complementary bits of which it is normally made up are disjoined. One obtains this result by increasing the temperature. The temperature to which half of the molecules of DNA is denatured is called molecular Melting point. The denaturation takes place when the shocks which had with the temperature arrive to " casser" the Hydrogen bonds binding the two bits. When the temperature falls down, the complementary chains réassocient two by two with reappearance of the connections H. the nucleotidic composition of the chain has an effect on the melting point: chains containing many bases C and G (implying 3 connections H between nucleotides in opposite on the two bits) will be more difficult to denature than chains containing more bases has and T (2 connections).

The renaturation is the opposite operation of reassociation of the two bits of the DNA which recombine in only one molecule bicaténaire.

The denaturation of the DNA can be done with a Thermocycleur.

Denaturation of proteins

In aqueous solution, a Protéine even adopts a structure folded up on it. This structure, known as " native" , is essential to allow him to provide its function. The process of denaturation is that by which the chain of protein is unfolded, thus abolishing the capacity of protein to fulfill its natural function.

Several physical or chemical conditions can cause the denaturation of proteins:

  • heat: thermal agitation causing the rupture of the interactions (hydrogen bonds, interactions of van der Waals) within the heart of the structure of protein.
  • pH: the acidity or the extreme alkalinity of the solution will lead to the Protonation or the deprotonation of a great acido-basic number of functions, which will disturb the ionic interactions stabilizing the protein
  • the Solvant: the folding up of proteins is conditioned by interactions between the aqueous environment, very polar, and surfaces it proteins. The transfer in an organic solvent destroys these interactions and generally leads to the denaturation of protein.
  • the presence of Detergent S: as in the case of solvent above, the presence of detergents can interfere with the interactions protein-solvent.

See too

  • Spirit methylated

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