Protein

Highmolecular polymer from different amino acids (polypeptide chain) formed in the ribosomes of the celln. Proteins show an extraordinary variety of amino acid sequencesand of the resulting structure, they can contain lipids, sugar and other groups of substances as well as metals and accordingly possess numerous properties and functions, which can also be modified by chemical modifications, such as phosphorylation, reversible, in the course of metabolic processes.

Proteins are made up of amino acids. Proteins belong to the basic building blocks of all cells. They not only give the cell structure, but are the molecular "machines" that transport substances, pump ions into and out of cells, recognize chemical reactions catalyse and signal substance. The building blocks of proteins are certain amino acids known as proteinogenic, i.e. building proteins, which are linked to chains by peptide bonds. Humans have 21 different amino acids - the 20 long known - and selenocysteine.

The amino acid chains can have a length of up to several 1000 amino acids, whereby amino acid chains with a length of less than approx. 100 amino acids are called peptides and are referred to as proteins only from a larger chain length. The molecular size of a protein is usually expressed in kilo-Daltons (kDa).

Titin, with approx. 3600 kDa the largest known human protein, consists of over 30,000 amino acids and contains 320 protein domains.

https://en.wikipedia.org/wiki/Protein

^*) The protein titin also has the longest systematic name of a chemical compound, namely the sequence of more than 30,000 amino acid names in the correct sequence, i.e. in the primary structure of the protein. The name of Titin begins with "Methionyl..." and ends with "...isoleucin" and the reading of the name would take several hours, because the word consists of 189,819 letters.