What Is A Protein? - Protein - Protein Synthesis

What Is A Protein?
8/1/2006
Bioresearch Online
A protein (from the Greek protas meaning "of primary importance") is a complex, high-molecular-mass, organic compound that consists of amino acids joined by peptide bonds. Proteins are essential to the structure and function of all living cells and viruses.
Different proteins perform a wide variety of biological functions. Some proteins are enzymes, which catalyze chemical reactions. Other proteins play structural or mechanical roles, such as those that form the struts and joints of the cytoskeleton, which is like a system of scaffolding within a cell. Still more functions filled by proteins include immune response and the storage and transport of various ligands.
Proteins are a class of bio-macromolecules, alongside polysaccharides, lipids, and nucleic acids, that make up the primary constituents of biological organisms. Proteins are essentially polymers made up of a specific sequence of amino acids. The details of this sequence are stored in the code of a gene. Through the processes of transcription and translation, a cell reads the genetic information and uses it to construct the protein. In many cases, the resulting protein is then chemically altered (post-translational modification), before becoming functional. It is very common for proteins to work together to achieve a particular function, and often physically associate with one another to form a complex.