# Proteins **Proteins** are one of the four main classes of [[biological macromolecules]]. ## Protein Functions The primary functions of proteins: 1. Support 2. Transport - Active movement 3. Defense - i.e. [[The Complement System]] 4. Motion 5. Metabolism - Food-breaking enzymes 6. Regulation - Receptors & Co-receptors (Keys & Locks) --- **Allostery** is a process in which a change to one part of a protein affects another part of the same protein. - “noncovalent binding of a molecule that alters the conformation of a target protein” ## Classifications of Proteins Proteins have been classified into many different groups known as "protein families": - **Glycoproteins:** aaa - **Globulin:** A family of simple globular proteins that ## Protein Domains The zinc-finger is one of the most common system for DNA