What is the Study of Enzymology?

What is an Enzyme?

Enzymes are proteins that speed up chemical reactions in living organisms. The enzyme's name comes from the fact that it can "increase" the rate of a reaction. Enzymes are vital for life because they control chemical reactions that would otherwise happen too slowly to sustain life. Without enzymes, biochemical reactions would proceed at rates 10^4 to 10^6 times slower than they do with enzymes present. Enzymes are recognized as non-living catalysts, meaning that they are not affected by the reaction they speed up. Enzymes are therefore able to speed up a very large number of biochemical reactions. This is done in two steps. First, the enzyme binds to the substrate, which is the molecule that is being transformed by the reaction. The enzyme then changes shape slightly to fit the substrate like a key in a lock. This change in shape allows the molecule to be transformed easily.

Enzyme Reactions

Enzymes accelerate the rate of chemical reactions by lowering the activation energy required for those reactions to proceed. The rate of a chemical reaction is determined by the relative concentrations of reactants, the temperature, and the physical and chemical properties of the reactants. The activation energy is the energy required to begin a chemical reaction; it is the energy barrier that must be overcome for the reaction to proceed. Enzymes lower the activation energy for a reaction by providing a new pathway for the reaction to proceed. They do this by binding to the substrate, forming an enzyme-substrate complex. The enzyme-substrate complex is an intermediate in the reaction, with a lower activation energy. Enzymes are specific for one reaction or set of related reactions; this specificity is known as the enzyme’s specificity or enzymatic specificity. Enzymes differ from non-enzymatic catalysts, such as chemical catalysts, in that enzymes are proteins, whereas chemical catalysts are not proteins. Enzymes are also specific for the reaction conditions where they catalyze a reaction to proceed.

Types of Enzymes

Enzymes currently fall into two main categories: glycosylases and isomerases. Glycosylases catalyze reactions that remove various chemical groups (e.g., methyl groups or hydroxyl groups) from sugars and other molecules. Isomerases catalyze reactions that rearrange individual atoms in a chemical compound without forming or breaking chemical bonds between atoms. Ligases catalyze reactions that join two molecules together. Oxidoreductases catalyze reactions that transfer electrons between chemical compounds. Ex Conclusion

Proteases

Proteases catalyze reactions that break specific chemical bonds in proteins. Specific proteases break specific amino acid bonds in proteins. Proteases are also used in laundry detergents to break chemical bonds in protein-based stains on fabrics.

Glycosylases

Glycosylases catalyze reactions that remove various chemical groups (e.g., methyl groups or hydroxyl groups) from sugars and other molecules. In DNA sequencing, glycosylases are used to cleave the bases from the sugars that are covalently attached to them, so that the bases can be identified.

Isomerases

Isomerases catalyze reactions that rearrange individual atoms in a chemical compound without forming or breaking chemical bonds between atoms. In biochemistry, isomerases are used to rearrange molecules to make them more useful or easier to use. For example, certain isomerases rearrange molecules so that they are easier to break apart or easier to put together again.

Ligases

Ligases catalyze reactions that join two molecules together. Ligases are used in biochemistry to join two small molecules (e.g., DNA molecules).

Oxidoreductases

Oxidoreductases catalyze reactions that transfer electrons between chemical compounds. Oxidoreductases are used in biochemistry to transfer electrons to molecules (e.g., to reduce salt to a metal or to reduce a molecule with a triple bond).

Conclusion

While enzymes are used to initiate many chemical reactions, they are not used to stop chemical reactions. This is because enzymes are not 100% efficient, so there will always be some type of reaction occurring in biochemical systems that do not contain enzymes. If the enzymes were used to stop all chemical reactions, they would quickly become depleted. Instead, enzymes are used to start chemical reactions along with non-enzymatic catalysts. Non-enzymatic catalysts are used to stop the chemical reaction once it has proceeded far enough. This is because non-enzymatic catalysts are much more efficient than enzymes and are used in smaller quantities.