Enzymes are a class of catalysts that increase the rate of chemical reactions without being consumed or permanently altered by the reaction. Enzymes are responsible for facilitating and increasing the rate of many vital biochemical reactions in plants and animals. Enzymes are complex compounds containing nitrogen and are proteins that have high molecular mass and form a heterogeneous mixture when dissolved in water. Enzymes act very efficiently and are responsible for various reactions that occur in the body of living beings.
The catalysis in which enzymes act as a catalyst is called enzyme catalysis. Enzyme-catalyzed reactions occur in at least two steps. In the first step, an enzyme molecule and the substrate molecule or molecules collide and react to form an intermediate compound called the enzyme-substrate complex. Once the enzyme-substrate complex forms, the enzyme is able to catalyze the formation of the product, which is then released from the enzyme surface. Enzymes are characterized by their substrate specificity, which means that they are specific to certain substrates.
The mechanism of enzyme catalysis varies, but it is similar in principle to other types of chemical catalysis in that the crucial factor is a reduction of energy barriers between products and reactants. Enzymes reduce the activation energy required for a reaction to proceed in the forward direction and speed up the rate of the reaction by a million-fold in comparison to non-catalyzed reactions. Enzymes do not alter the ΔG of the reaction and do not have any effect on the spontaneity or equilibrium position of the reaction. The substrate binds to the enzyme primarily through hydrogen bonding and other electrostatic interactions.
