By Chris Marcano
Almost every aquatics industry professional has likely heard stories about the use of enzymes in water maintenance and for solving water quality problems. Many have also probably asked themselves along the way what, exactly, are enzymes? In performing a quick Google search on the word itself, one would likely come across the following Wikipedia answer:
Enzymes are large biological molecules responsible for the thousands of chemical interconversions that sustain life. They are highly selective catalysts, greatly accelerating both the rate and specificity of metabolic reactions from the digestion of food to the synthesis of deoxyribonucleic acid (DNA). Most enzymes are proteins, although some catalytic ribonucleic acid (RNA) molecules have been identified. Enzymes adopt a specific three-dimensional structure, and may employ organic (e.g. biotin [vitamin H or coenzyme R]) and inorganic (e.g. magnesium ion) cofactors to assist in catalysis.
If this description seems a bit confusing, do not be alarmed. After scrolling down a little further, and conducting a web query on what enzymes really do, one can actually yield a much more simple description. For example:
In enzymatic reactions, the molecules at the beginning of the process, called substrates, are converted into different molecules, called products. Almost all chemical reactions in a biological cell need enzymes in order to occur at rates sufficient for life. Since enzymes are selective for their substrates and speed up only a few reactions from among many possibilities, the set of enzymes made in a cell determines which metabolic pathways occur in that cell.
An everyday example
To provide a tangible, everyday example of what occurs between an enzyme and its substrate, think about it like the ring of keys one would carry everywhere they go to open various locks throughout their daily routine. Each of these keys will only open the lock for which it was specifically designed. Likewise, enzymes (keys) are specific as to what they are capable to catalyze (bacteria).
In relating this idea to swimming pool and hot tub maintenance, it is easy to understand how the formulation of an enzyme product is important to its application. For example, there are some enzymes that are formulated to focus heavily on non-living organic contaminants (e.g. sweat, lotion, urine, and sunscreen), which is introduced by bathers at an extremely high rate while swimming. Other enzyme products are designed to focus more on environmental factors (e.g. pollen, bird droppings, or even jet fuel that may land in those backyards located near an airport), which may cause water quality problems.
A technical explanation
In general, like all catalysts, enzymes work by lowering the activation energy (Ea) for a reaction, thus dramatically increasing the rate of the reaction. As a result, products are formed faster and reactions reach their equilibrium state more rapidly. Most enzyme reaction rates are millions of times faster than those of comparable un-catalyzed reactions. As with all catalysts, enzymes are not consumed by the reactions they catalyze, nor do they alter the equilibrium of these reactions. However, enzymes do differ from most other catalysts in that they are highly specific for their substrates. In fact, enzymes are known to catalyze approximately 4,000 biochemical reactions. A few RNA molecules called ribozymes also catalyze reactions, with an important example being some parts of the ribosome.
Enzyme activity can be affected by other molecules. Inhibitors are molecules that decrease enzyme activity; activators are molecules that increase activity. For example, many drugs and poisons are enzyme inhibitors. Activity is also affected by temperature, pressure, chemical environment (e.g. pH), and the concentration of substrate. Some household products use enzymes to speed up biochemical reactions (e.g. enzymes in biological washing powders breakdown protein or fat stains on clothes, while enzymes in meat tenderizers breakdown proteins into smaller molecules, making the meat easier to chew).