We Couldn't Live Without Enzymes
Enzymes are a type of catalyst, which are substances that speed up a chemical reaction.
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Transcript
The chemical reactions within the body would not happen often enough, or quickly enough, for life to persist without the help of substances called enzymes.
Enzymes are a type of catalyst, which are substances that speed up a chemical reaction.
Each enzyme is specific and usually only speeds up one kind of reaction. The molecules enzymes act upon are called substrates.
The acceleration of the chemical reaction is called catalysis. It begins when the substrate binds to the enzyme. This binding occurs on a specific part of the enzyme, called the active site.
But how exactly do enzymes and substrates work? Let’s look at the two main models that have been proposed for this process.
The lock-and-key model proposes that the active site of each enzyme has a unique shape that is complementary to the shape of the substrate molecule.
Only the correctly shaped key (substrate) will fit into the corresponding lock (enzyme). Once substrate and enzyme match up, catalysis will begin.
In contrast, the induced-fit model suggests that the active site of the enzyme is not the exact complementary shape of the substrate, but is instead slightly flexible.
When the substrate binds to the enzyme, the shape of the enzyme’s active site changes.
When the active site changes, catalysis can occur.
Enzymes are a type of catalyst, which are substances that speed up a chemical reaction.
Each enzyme is specific and usually only speeds up one kind of reaction. The molecules enzymes act upon are called substrates.
The acceleration of the chemical reaction is called catalysis. It begins when the substrate binds to the enzyme. This binding occurs on a specific part of the enzyme, called the active site.
But how exactly do enzymes and substrates work? Let’s look at the two main models that have been proposed for this process.
The lock-and-key model proposes that the active site of each enzyme has a unique shape that is complementary to the shape of the substrate molecule.
Only the correctly shaped key (substrate) will fit into the corresponding lock (enzyme). Once substrate and enzyme match up, catalysis will begin.
In contrast, the induced-fit model suggests that the active site of the enzyme is not the exact complementary shape of the substrate, but is instead slightly flexible.
When the substrate binds to the enzyme, the shape of the enzyme’s active site changes.
When the active site changes, catalysis can occur.
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