Biochemistry 2280A Lecture Notes - Lecture 4: Egg White, Enzyme Kinetics, Leonor Michaelis
Document Summary
Some common characteristics allow many proteins to function. Protein flexibility is critical for many different functions. Proteins that are not rigid can undergo modest changes in structure called conformational changes . Conformational changes can be caused by minor changes in the environment, or by binding of some other molecule, and often involve changes in the relative position of structural domains. Conformational changes provide the driving force behind motor proteins, the sensory function of receptors, the control of enzyme activity, the transmission of signals, etc. Thus many proteins have evolved to bind to particular molecules with great specificity, using multiple weak bonds (fig. Generally, a small area of the protein surface is complementary to the structure of another molecule (called a ligand ). In the case of enzymes, this area is termed the substrate-binding site or just active site . Thus a protein might recognize just one or two out of thousands of other molecules in the cell.