What is an apoenzyme?

Explanation

### Step-by-Step Text Solution:

1. **Definition of Apoenzyme**: An apoenzyme is the inactive form of an enzyme. It is the protein component of an enzyme that requires a cofactor to become active.

2. **Components of Apoenzyme**: Apoenzymes consist solely of the protein part of the enzyme. They do not include any non-protein components that are necessary for enzymatic activity.

3. **Activation of Apoenzyme**: Apoenzymes become active when they bind to a cofactor. A cofactor can be a metal ion or a coenzyme (which is often a vitamin or a derivative of a vitamin).

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