Proteins

Synonyms in a broader sense

protein, proteins, protein, food intake

Definition

Proteins are also called proteins and are found in many of our foods in varying concentrations. As so-called macromolecules, they are composed of small building blocks, the amino acids, and have different modes of action depending on the composition of the up to twenty different amino acids. Proteins make up a large part of our muscles and are therefore also involved in maintaining and building muscles.

Proteins are also an important building block in the recovery phase during regeneration after physical exertion. Amino acids form long chains and thus shape the different proteins. The three-dimensional structure and arrangement of the amino acids determines the different modes of action and functions of the proteins.

The genetic material of each organism is also contained in the proteins in the form of a code. Proteins can be composed of essential and non-essential amino acids. Essential amino acids cannot be produced by the body and must therefore be taken in with food.

Proteins are usually composed of carbon, hydrogen, oxygen and nitrogen atoms and also contain sulfur, iron, phosphorus and zinc. About half of the human dry matter is made up of proteins, making them the most important building block of the organism. Proteins are also responsible for fluid transport in the body and are therefore an important component of human blood.

Chemical basics

Generally speaking, proteins are so-called macromolecules (very large chemical particles), which consist of amino acids strung together. Amino acids are produced by the cell organelles, the ribosomes, in the body. In their function in the human body, proteins are comparable to small machines: they transport substances (intermediate and end products of metabolism), pump ions (charged particles) and, as enzymes, promote chemical reactions.

There are 20 different amino acids, which in turn are used to build proteins in various combinations. The amino acids are divided into two groups: Basically they have the same structure, all amino acids consist of an amino group (NH2) and a carboxyl group (COOH). These two groups are bound to a carbon atom and thus linked to each other.

In addition, there is a hydrogen atom (H) and a side chain (residual group) on the central carbon atom. The difference between the amino acids is then determined by which atoms are attached to this residual group. Glycine, for example, is the simplest amino acid, since only one hydrogen atom is attached to its side chain.

If at least 100 amino acids are strung together, we speak of a protein. Less than 100 amino acids are called peptides. However, the structure does not always have to be purely chain-shaped, but can also be made up of several closely adjacent chains.

Accordingly, the variety of proteins is very large. The final function of the protein is determined by its structure. The protein structure can be described in four different ways.

• Amino acids that can be produced by the body itself
• Amino acids that have to be taken in with food (=essential amino acids).
• Primary structure (only the order of amino acids within the protein)
• Secondary structure (local spatial arrangement (alpha-helix) of the amino acid in screws or unfolded strands)
• Tertiary structure (entire spatial structure of the chain, including the side chains)
• Quaternary structure (entire spatial situation of all chains)