Proteins are a primary constituent of living things and one of the chief classes of molecules studied in biochemistry. Proteins provide most of the molecular machinery of cells. Many are enzymes or subunits of enzymes. Other proteins play structural or mechanical roles, such as those that form the struts and joints of the cytoskeleton. Each protein is linear polymers built of amino acids. Proteins are also nutrient sources for organisms that do not produce their own energy from sunlight and/or are unable to fix nitrogen. Proteins can interact with one another and with others molecules to form complexes.
Index of chapters and main sections
- The chemistry of proteins
- Protein structure and folding
- Types of Protein