Our health and good mood depend largely on our diet. Each type of food is made up of one or more nutrients, which are chemical substances that allow our bodies to function properly.
Among the main nutrients that our bodies need are the proteins, whose name comes from the greek proteins, which means “first”, which shows the primary importance that this compound has for life.
Proteins are present in all living cells and are natural polymers formed by the condensation polymerization reaction between α-amino acids (α-aa - where the amine group is on the second carbon counting from the carboxyl group) joined by peptide bonds. This means that the bond between an amino group (RNH2) of an amine group molecule with the carboxyl group (R1CO2H) of another molecule from the group of carboxylic acids. The result is the formation of an amide group (RNHCOR1) and the release of a water molecule (H2O):
These α-aa unite forming proteins with more than 100 peptide bonds. Below is an example of two generic α-aa:
There are 20 amino acids that are found in proteins, below are some of them:
However, only nine amino acids present in proteins are considered essential for us, because our body does not synthesize them and we must then acquire them through food.
Every protein has a primary structure which is the sequence of amino acids that are joined together in the main chain. But there are also secondary, tertiary and quaternary structures of proteins, which are interactions that occur in portions or parts of the same protein or also between several protein chains. Some of these interactions are hydrogen bonds it's from disulfide.
To find out which foods are sources of protein and why these substances are so important for the maintenance of life, read the text Function of proteins and their sources in food.
By Jennifer Fogaça
Graduated in Chemistry
Source: Brazil School - https://brasilescola.uol.com.br/quimica/composicao-quimica-das-proteinas.htm