Enzymes are protein molecules that function by triggering chemical reactions in cells throughout your body. Each of these molecules has its own characteristic shape and affects only certain types of materials. Without the effects of enzymes, your body would be unable to transform its internal chemicals fast enough to sustain life.
Each enzyme contains a specific sequence of proteins, and it is this sequence that determines its basic activity inside your body. In addition, an enzyme can contain organic or inorganic non-protein substances called cofactors, which help determine its overall shape and/or function. The shape of any given enzyme allows it to link up with and transform only one or two types of materials in your body, referred to during enzymatic reactions as substrates. Typically, an enzyme gets its name from the type of substrate it affects. For example, the enzyme sucrase transforms the sugar sucrose into the sugars fructose and glucose. The enzyme lipase chemically transforms the lipid, or fat, called triglyceride.
On one level, the human body can be accurately viewed as a series of ongoing chemical reactions. Enzymes achieve their effects by speeding up most of the reactions inside your cells to approximately one million times the rate your body could maintain without enzymes, according to Charles E. Ophardt of Elmhurst College. Without this drastically increased rate of activity, there simply wouldn’t be enough ongoing chemical transformations to sustain your life. Each of your cells produces roughly 3,000 different enzymes, and alteration or absence of a single one of these enzymes can have potentially life-threatening effects.
Enzymes are not permanently transformed by the chemical reactions they trigger in substrate materials. Instead, after a given reaction occurs, each enzyme in your body reassumes its characteristic shape and attaches itself to the next available substrate; after it attaches itself, the next chemical reaction occurs. Enzymes can also undo the changes they make in substrates and return these materials to their original chemical states. Because of these basics qualities, enzymes perform their jobs with a very high degree of efficiency.
Your body temperature and relative acidity, or pH, can alter the effects of enzymes by changing the shape of their individual proteins. Enzyme activity in your body can also change or stop in the presence of substances called inhibitors, which keep your enzymes from doing their jobs. Conversely, substances called activators can boost your enzyme activity and make them work on more substrates than normal. Activators can come from your diet or from internal sources. Types of inhibitors include both poisons and medications.