Coenzymes
The word enzyme comes from the Greek word “en” which means in, and “zyme” meaning yeast, together, “in yeast”. Enzymes are made up of protein and nonprotein components. The two together constitute a fully active holoenzyme. The protein portion of the holoenzyme is known as the apoenzyme while the nonprotein component, is referred to as a coenzyme. When the two moieties (from French, meaning, “halves”) are separated from each other, neither possesses the catalytic properties of the original conjugated protein. Enzymes are both part of larger proteins, as well as proteins themselves, and are used in biochemistry to break down proteins, lipids and carbohydrates in the digestive process.
A coenzyme is often observed in the form of a medium-sized organic molecule called a prosthetic group composed entirely of a vitamin, or partially, or from a vitamin derivative. In addition, coenzymes may be comprised of a mineral, or a metal ion (an atom with a net electric charge), in which case they are known as cofactors.
Although some enzymes are attached very tightly to their coenzymes, others can be parted easily; in either case, the parting almost always deactivates both partners. However, by simply mixing the apoenzyme and the coenzyme together, the fully active holoenzyme can often be reconstituted. Sir Arthur Harden (1865-1940) proved this in boiling experiments with yeast. The experiments were designed to separate one moiety from the other (and in the process presumably destroy the protein portion). For his discovery that such deactivated yeast could be reactivated, he was jointly awarded the 1929 Nobel Prize. http://www.answers.com/topic/enzyme
Even though it is primarily the nature of the apoenzyme, rather than that of the coenzyme which determines the specificity of the reaction, it is important to recognize that in most instances, the coenzyme participates directly in the catalytic reaction. For example, the coenzyme may serve as an intermediate carrier of a group being transferred from one substrate to another. Also, the same coenzyme may be associated with many enzymes which catalyze different reactions.
Thus the coenzyme’s presence is required for the activity of many enzymes. In general, the coenzymes function as acceptors of electrons or functional groupings that are removed from the substrate. A well-known coenzyme Folic acid (not to be confused with Fulvic Acid) is involved in the metabolism of carbon units.
In the context of agriculture the coenzymes with a particular mineral or ionic structure contain the atoms of unique trace elements responsible for the catalytic properties so important for plant nutrition.
