In an enzyme, active sites/pockets/crevies are present on

Options

A. `1^(@)` structure
B. `2^(@)` structure
C. `3^(@)` structure
D. all of these

Answer

To solve the question regarding where active sites, pockets, and crevices are present in an enzyme, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Structure of Proteins**:
- Enzymes are primarily proteins, and their structure is categorized into four levels: primary (1°), secondary (2°), tertiary (3°), and quaternary (4°) structures.

2. **Identify Each Structure**:
- **Primary Structure (1°)**: This refers to the linear sequence of amino acids in a polypeptide chain.
- **Secondary Structure (2°)**: This involves the folding of the polypeptide chain into structures such as alpha helices and beta sheets.
- **Tertiary Structure (3°)**: This is the overall three-dimensional shape of a single polypeptide chain, which includes the arrangement of secondary structures and the formation of active sites, pockets, and crevices.
- **Quaternary Structure (4°)**: This structure involves the assembly of multiple polypeptide chains into a functional protein complex.

3. **Focus on Active Sites**:
- Active sites, pockets, and crevices are formed during the tertiary structure of the enzyme. They are essential for the enzyme's function as they provide specific regions for substrate binding.

4. **Conclusion**:
- Based on the understanding of protein structures, we conclude that the active sites, pockets, and crevices are present in the tertiary structure (3° structure) of an enzyme.

5. **Final Answer**:
- The correct option is **C) 3 degree structure (tertiary structure)**.