Structure Of Enzymes At A Glance
Enzymes: An Introduction
Enzymes are typically proteins, responsible for the catalysis of reactions. There are specific mechanisms by which this catalysis is accomplished. Enzymes bind temporarily to reactants involved in the particular reaction. This binding promotes reaction speed increases by decreasing the overall activation energy of the reaction. The activation energy is the amount of energy required to initiate a reaction. If there is not enough energy present to overcome the activation energy requirements, the reaction does not occur. In this manner, reactions that are unfavorable, can be made favorable due to enzymes!
Enzymes: Mechanical Digestion
Mechanical digestion is accomplished through two particular methods: mastication and peristalsis. Mastication is the process of breaking down foods by chewing. Mastication requires saliva, which contains enzymes, to aid in the breakdown. Peristalsis is the process by which food is moved through the digestive system. It is accomplished by smooth muscle contractions. Mechanical digestion prepares food for the next steps of chemical digestion.
Enzymes: Chemical Digestion
Chemical digestion requires enzymes. These enzymes are manufactured and secreted by the stomach and accessory organs: the pancreas, liver, and gall bladder. Chemical digestion is defined as the breakdown of complex chemicals into simple chemicals that are absorbed by the body. Complex chemicals include fats, proteins, and carbohydrates. This chemical digestion primarily occurs in the stomach and small intestines. Once digested, the chemicals are absorbed into the body, where they are used for cell metabolism. Cell metabolism is critical for maintenance of overall general health. Metabolism is responsible for growth, development, reproduction, structure maintenance, and environmental response mechanisms. All of these functions are critical for life.
Enzyme Structure and Function
The golden rule that holds true for all cellular biology, molecular biology, and biochemistry: Structure dictates function. This holds true because enzymes are extremely specific. The common example is that of a lock and key. There is only one key that will open a specific lock. There is no such thing as a universal lock for enzymes. Enzymes catalyze specific reactions.
Cofactors and Coenzymes
It is common for enzymes to require cofactors or coenzymes for proper functioning. This adds another level of regulatory factors. Cofactors are non-protein substances, required by some enzymes for activation. Cofactors are commonly vitamins or minerals. It is also common for more than one enzyme to be required by the body. Coenzymes are additional enzymes required to efficiently speed a reaction in addition to the main enzyme. Coenzymes are responsible for the movement of chemical groups (commonly cofactors) between enzymes.
Enzyme Kinetics and Inhibition
Enzyme kinetics is the study of the rates of enzyme function. Enzyme function regulates reaction rates. Reaction rates determine how quickly specific products are made. Excess products are commonly associated with many diseases and conditions. Enzyme kinetics are used for much scientific research in biochemistry. The rates of enzyme functions are affected by many things including pH and temperature. Inhibitors of enzyme function also exist. Ways to inhibit specific enzymes are critical to scientific research. The ability to control the rate at which enzymes catalyze reaction is thought to be critical in disease treatment and prevention methods.