text: Transition metals in general catalyze an incredible array of reactions, and nature makes full use of these abilities in metalloenzymes. As a result, there are many different purposes for transition metals in proteins.\n\nOften the metal center serves as a Lewis Acid to help catalyze a reaction, as is found in many metalloproteinases.\n\nSince metals can be reversibly oxidized and reduced (which is not true of normal amino acids) they play an important role in reduction and oxidation reactions. This is esepecially important for processes like photosynthesis and oxidative phosphorylation.\n\nMetal centers are also important for storing certain compounds, such as oxygen. We all rely on hemoglobin and myoglobin for oxygen storeage.\n\nThere are many other uses as well, but these are most of the major ones.