ABSTRACT
Enzyme catalysis A catalyst is a substance that increases the rate of a reaction. When these reactions occur in biological systems, the catalyst is often a protein, and such catalytic proteins are referred to as enzymes. Whether a catalyst is protein based or not it should emerge at the end of a sequence of elementary steps unchanged, ready for use in another series of reactions. All catalysts operate by lowering the energy required for a process to occur; therefore the activation energy (Ea) for a step is reduced.
