Active site and induced fit
The active site is the pocket where the substrate binds. In induced fit, the enzyme changes shape slightly around the substrate for a tighter grip.
Last updated
Analogy
A glove that moulds to your hand as you put it on.
In practice
Hexokinase closes around glucose when it binds, which keeps water out and helps transfer a phosphate.
Practice
Flashcards
- What is induced fit?The enzyme changes shape slightly when the substrate binds, giving a tighter fit.
Questions people ask
What is the difference between lock-and-key and induced fit?
Lock-and-key pictured a rigid enzyme with a perfectly matching shape. Induced fit is the better model: the enzyme and substrate both adjust as they meet, so the grip tightens as the reaction begins. This helps the enzyme strain the substrate toward the transition state.
What are cofactors and coenzymes?
Cofactors are non-protein helpers that many enzymes need, such as zinc or magnesium ions. Coenzymes are organic helpers, often made from vitamins, such as NAD+. They carry small groups or electrons between reactions. That is one reason that vitamin shortages can cause disease.