The correct answer is option 2: All enzymes are proteins.

Proteins and enzymes are closely related but not synonymous terms. Proteins are large, complex molecules that play various roles in the body, including providing structure, supporting immune function, and acting as enzymes. Enzymes, on the other hand, are a specific subtype of proteins that act as catalysts in biochemical reactions.

Option 1, which states that all proteins are enzymes, is incorrect. While some proteins do act as enzymes, not all proteins have catalytic activity. Proteins have many other functions in the body beyond being enzymes.

Option 3, which claims that none of the enzymes is protein, is also incorrect. Enzymes are a subclass of proteins and are composed of amino acids, just like other proteins. They have a specific structure that allows them to bind to substrate molecules and speed up chemical reactions.

Option 4, none of the proteins is an enzyme, is also incorrect. As mentioned earlier, some proteins do have enzymatic activity and function as enzymes.

In conclusion, option 2 is the correct statement, as it acknowledges that all enzymes are proteins, but not all proteins are enzymes.