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Enzymes
Enzymes are biological molecules that catalyze the rates of reactions in the body without
getting used up in the process. They have active sites onto which the substrate binds. Binding is
specific, for instance, a given enzyme can only break down a specific substance. After binding to
the active site, the substrate is broken down and the products released. The enzyme takes part in
the process but is not consumed itself. Substrates bind to the enzyme and react forming products
which are then released. The enzyme is then released to take part in another reaction cycle.
Enzymes work under specific conditions such as temperature ranges; most work optimally under
normal body temperature which is at 37C. Increase or decrease in temperature alters the protein
structure of these enzymes thereby reducing their activity. They are also substrate-specific such
as a given substrate can only be broken down by a given enzyme. Ionic requirements are also
important, for instance, enzymes require specific pH levels for optimum action. Alkalinity or
acidity of the medium of the reaction affects the rate at which the reaction will occur. Enzymes
also require co-factors. These are substances such as zinc and manganese that enzymes need to
catalyze reactions effectively (Sumner, J.B. and Somers, G.F., 2014).
The lock and key hypothesis is used to explain the specificity of enzymes. Only a specific
substrate can bind the active site of a given enzyme, the key is the substrate while the lock is the
active site of the enzyme. The conformation of the substrate should be complementary to that of
the enzyme’s active site for binding to take place and consequently, for the reaction to occur. The
substrate binds to the active site resulting in changes in electrons in bonds present in the substrate
causing a reaction that eventually leads to product formation.
Activation energy is the energy that atoms must acquire before a reaction can occur. It is
the energy required for the transition phase of a reaction. It is necessary for a reaction to start.
