How are Biochemical Reactions Catalyzed?
Biochemical reactions in living things are catalyzed (sped up) by enzymes.
- Enzymes are special proteins (sometimes RNA) that act as biological catalysts.
- They make reactions happen millions of times faster than they would on their own.
Steps in Enzyme Catalysis
- Substrate Binding
- The molecule that needs to react (substrate) attaches to the enzyme at a special spot called the active site.
- Formation of Enzyme–Substrate Complex
- The enzyme holds the substrate in the correct position, like a key fitting into a lock.
- Lowering Activation Energy
- The enzyme reduces the energy needed to start the reaction, making it easier and faster.
- Reaction Happens
- Bonds are broken or new bonds are formed → the substrate changes into the product.
- Product Released
- The product leaves the enzyme, and the enzyme is free to work again.
Other Helpers
- Sometimes enzymes need cofactors (like metal ions) or coenzymes (like vitamins) to assist in the catalysis.
Example
- Enzyme: Amylase (in saliva)
- Reaction: Breaks starch into sugar (maltose)
- Without enzyme → reaction would be very slow.
- With enzyme → reaction happens quickly at body temperature.
In short:
Biochemical reactions are catalyzed by enzymes, which work by binding the substrate, lowering activation energy, and speeding up the conversion to products.