Enzymes are proteins that act as biological catalysts in living organisms. They speed up chemical reactions that take place in cells, allowing the cell to build things or take them apart as needed. This is necessary for life to exist as we know it.
Enzymatic activity refers to the rate at which an enzyme catalyzes a specific reaction. The activity of an enzyme can be influenced by a variety of factors, including:
- Substrate Concentration: Enzymes work by binding to their substrate(s) at a specific location called the active site. The rate of reaction initially increases with increasing substrate concentration, but it eventually reaches a maximum speed, known as Vmax. This is when all of the enzyme molecules are bound to substrate molecules.
- Enzyme Concentration: The rate of an enzymatic reaction can also be increased by increasing the amount of enzyme, as long as there is an excess of substrate.
- Temperature: Every enzyme has an optimum temperature at which it works most efficiently. Human enzymes typically have an optimum temperature of around 37°C. If the temperature gets too high, the enzyme can denature and lose its functionality.
- pH: Similarly, every enzyme has an optimum pH at which it works best. For example, pepsin (a digestive enzyme) works best at a highly acidic pH, whereas trypsin (another digestive enzyme) works best at a slightly alkaline pH.
- Inhibitors: Substances known as inhibitors can decrease enzymatic activity. Competitive inhibitors work by binding to the active site of the enzyme, preventing the substrate from binding. Non-competitive inhibitors bind to a different part of the enzyme, causing it to change shape and preventing the substrate from binding effectively.
The activity of an enzyme is usually measured in units of moles of substrate converted per unit time. Depending on the specific requirements of your experiment, there are various methods available for measuring enzymatic activity, such as spectrophotometric assays, radioactive isotopes, or chromogenic substrates.
