In biochemistry, a substrate is the molecule acted on by an enzyme to produce a product.p37
The general equation for an enzyme reaction is:
- Substrate + Enzyme –> Substrate:Enzyme –> Product:Enzyme –> Product + Enzyme
An example: Sucrase, 400 times the size of its substrate sucrose, splits the sucrose into its constituent sugars, which are glucose and fructose. The sucrase bends the sucrose, and strains the bond between the glucose and fructose. Water molecules join in and make the cleavage in a fraction of a second.
- Enzymes increase the rate of reaction up to 10 billion-fold and are effective in tiny amounts. One enzyme molecule may convert 1000 molecules of substrate a minute, and some are known to convert 3 million in a minute.p39
- A substrate may be capable of many reactions. One enzyme will only carry out one of the many reactions of which a substrate is capable.
