Proteins. The amino acids

Amino acids
It is impossible to speak of proteins without having to deal with amino acids, basic structural constituents, who, like links in a chain, are the necessary elements, linked together, form the protein molecule. The proteins differ primarily by the number, nature and binding order of a few amino acids with others. Despite the variety and complexity of naturally occurring proteins, all of them are made from only twenty different amino acids, called essential, with only the eight listed below those considered essential or not synthesized from others the body.

1) Phenylalanine
2) Isoleucine
3) Leucine
4) Lysine
5) Methionine
6) Threonine
7) Tryptophan
8) Valine

The molecular structures of proteins are composed of long chains of amino acids called helical peptide, in which these elements are wrapped around an imaginary axis.

The carboxyl of one amino acid reacts with the amino group of another amino acid, removing a water molecule and forming an amide binding. This new compound is named peptide, and the union is called a peptide. The peptide will be in their endpoints radical free NH2 and COOH, can they, in turn, link with a peptide binding to two new amino acids to form more complex molecules called polypeptides precisely.

The proteins are then macromolecules formed by the joining of numerous amino acids linked by peptide-type junctions. This approach is well tested and accepted by modern biochemistry can give an idea of why protids found in nature are so numerous and so different from each other. By reacting with each other, the two simplest amino acid, glycine and alanine, two peptides were obtained isomers, ie the same chemical formula, but structurally different, according to the carboxyl group of glycine than the one one with a peptide bond amide group of alanine or vice versa.

Variety of proteins
If instead of two amino acids are set to react three combinations that are obtained by the different way of succession of these compounds based on the polypeptide that is formed then increase the number of six. Further expanding the number of amino acids, the number of possible isomers increases according to the law of permutations up to put very great: for example, with 5 amino acids can have 120 polypeptides, with ten, 3628000; with fifteen, 1307. 674,368,000, and so on. If you think that in the hydrolysates of the various analyzed protides found twenty kinds of amino acids will be different thus an idea of why proteins in nature are so numerous and diverse from each other and reach a level of expertise as extremely high .

*Automatic Translation