Enzymes can be found all around us. They exist in all forms of lives, including human, plants, bacteria, and other organisms. Any living organism needs enzymes to function properly. Chemically, enzymes are naturally occurred proteins, basic function of which is to speed up the process and efficiency of a chemical reaction without being consumed in the process. In another word, an enzyme is a protein-based catalyst. Enzymes catalyze all kinds of chemical reactions that are involved in growth, blood coagulation, healing, diseases, breathing, digestion, reproduction, and many other biological activities. On biological aspects, enzymes are instrumental substances to many functions in living organisms.
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Enzymes are competent of participating in signal transduction, where a chemical or physical signal is transmitted through a cell as a series of molecular events, and a cellular response ultimately appeared. The most common enzymes in signal transduction are protein kinases that catalyze protein phosphorylation. |
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Large molecules can be broken down by enzymes into small fragments which can then be absorbed by human body easily. Many nutritional ingredients are in the form of large molecules such as sugar, proteins, and fat, which cannot be up taken easily by human body. Hence, these ingredients are broken down by enzymes into smaller pieces before absorption, and this process is called catabolism. Following absorption, the small molecules will be used as building blocks to refresh the body through tissue repairing, regeneration, and growth, and this process is called anabolism. Many enzymes need to be employed in catabolism and anabolism, such as amylases and proteases. |
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Enzymes can generate energy for living organisms. Adenosine triphosphate, also known as ATP, is the main storage form of chemical energy. ATP is a charged battery that can release energy that powers biological activities. Enzymes are the transformer to turn energy into proper chemical forms and store it in ATP molecules. Most of these enzymes are called ATP synthases. |
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Some enzymes in the cell membrane act as ion pumps to move ions across a plasma membrane against their concentration gradient involved in active transport mechanisms. These primary ion transporters could convert energy from various sources including ATP, sunlight, and other redox reactions, to potential energy stored in an electrochemical gradient. |
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In organisms, there are always some nonnutritive substances from external environment or produced by the body itself, which can’t be either transformed into cellular constituents or employed as energy source. Herein, they need to be converted into products to be excluded or utilized as physiological, pathological, or toxicological components. Enzymes involving in this procedure might be a single enzyme, a complex encompassing various enzymes or an enzyme system, which perform a series of biochemical reactions though oxidization, reduction, hydrolysis and so on. |
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Cell Regulation Enzymes can move parts of a cell’s internal structure and reorganize them to regulate cell activities. They deliver packages from one part to another inside cells, pull chromosomes apart when the cells undergo mitosis, and also pull cilia to trigger cell movement or to help cells move mucus up your airway as a routine to keep the airway clear. Common enzymes involved in these movement mentioned above are myosin ATPase, kinesin ATPase, and dynein ATPase. |
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Other Functions In addition, enzymes are also able to generate movement, with myosin hydrolyzing ATP to generate muscle contraction, and transport intracellular substances around the cell as part of the cytoskeleton. Enzymes are important players in many other functions, including immune responses and aging processes. Luciferase is the major reason for the glowing of fireflies, and enzymes in virus are involved in infecting cells or the release of virus particles from host cells. |
