Protein

Eiweiß, hochmolekulares Polymer aus verschiedenen Aminosäuren (Polypeptidkette), das in den Ribosomen der Zellen gebildet wird. Proteine zeigen eine außerordentliche Vielfalt der Aminosäure-Sequenz und des resultierenden Aufbaus, sie können Lipide, Zucker und andere Stoffgruppen sowie Metalle enthalten und dementsprechend zahlreiche Eigenschaften und Funktionen besitzen, die zudem im Rahmen von Stoffwechselvorgängen durch chemische Modifikationen, wie etwa durch Phosphorylierung, reversibel modifizierbar sind.

Proteins, colloquially also called proteins, are macromolecules 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 are 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://de.wikipedia.org/wiki/Protein _{(Wikipedia CC-by-sa-3.0)}

^*) 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.