Active site of enzyme is formed by

Options

A. Primary structure of protein
B. Secondary structure of protein
C. Tertiary structure of proteoin
D. Quaternary structure of protein

Answer

To answer the question about what forms the active site of an enzyme, we can break down the information step by step:

### Step-by-Step Solution:

1. **Understanding the Active Site**:
- The active site of an enzyme is a specific region where substrate molecules bind. It is crucial for the enzyme's catalytic activity.

2. **Structure of Proteins**:
- Proteins have different levels of structure: primary, secondary, tertiary, and quaternary.
- **Primary Structure**: This is the sequence of amino acids in a polypeptide chain.
- **Secondary Structure**: This involves the folding or coiling of the polypeptide chain into structures like alpha-helices and beta-pleated sheets.
- **Tertiary Structure**: This is the overall three-dimensional shape of a single polypeptide chain, formed by the folding of the secondary structures.
- **Quaternary Structure**: This refers to the assembly of multiple polypeptide chains into a functional protein.

3. **Formation of the Active Site**:
- The active site is formed by the specific folding of the protein, which creates a unique three-dimensional shape that is complementary to the substrate.
- This folding is primarily determined by the tertiary structure of the protein.

4. **Conclusion**:
- Therefore, the active site of an enzyme is formed by the **tertiary structure of the protein**.

### Final Answer:
The active site of an enzyme is formed by the **tertiary structure of the protein**.

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