Date: Fall 2011
Why are small amounts of enzymes able to catalyze large amounts of substrates?
Because Enzyme molecules do not get consumed themselves during the catalytic process and are regenerated/recycled at the end of the catalytic reaction. So one molecules of the enzymes catalyses many substrate molecule turn by turn.
An enzyme can catalyze a large amount of substrate (reactant) because the
enzyme isn't destroyed
By the reaction, it just keeps "recycling".
Remember, enzymes are catalysts that help start chemical reactions. They do so by lowering the activation energy required for that reaction to start.
So depending upon your reaction of interest, the activation energy may just be low enough, that a small amount of enzymes are required to start a reaction.
The same would apply for the opposite, where enzymes can be inhibitors which change the substrate properties that prevent a reaction from happening. One small enzyme could be just enough to change the properties (its shape for one) to prevent the binding of other catalyst.
Overall, you're dealing with reactions at very tiny dimensions and scales. Any minor change, in the nano levels, is amplified in the higher dimensions.
An enzyme is an organic catalyst. It's purpose is to make a reaction proceed more quickly and/or easily and it usually does so by lowering the reaction energy required. In a test-tube, to oxidise sugar to CO2 and H2O requires temperatures approaching 200C. In the presence of a suitable enzyme, such as glucose oxidase, the reaction can proceed at a much lower temperature - one safe enough to carry on inside your body.
The important thing about the enzyme is that at the end of the reaction, the enzyme is unchanged and is available to take another molecule of glucuse and start again. One enzyme molecule can process hundred, thousands or even millions of glucose molecules before it become damaged and has to be replaced. It is because of thise replacement that we require a certain daily intake of many vitamins and minerals such as the B group, vitamin C and D. All of these act within the body as enzymes or key ingredients to manufacture enzymes within the body.
Lab Technician Barkly College - Secondary
Tennant Creek NT AUSTRALIA
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Update: June 2012