Enzymes having slightly different molecular structure but performing identical activity are called

Options

A. holoenzymes.
B. isoenzymes.
C. apoenzymes.
D. Coenzymes.

Answer

To solve the question regarding enzymes that have slightly different molecular structures but perform identical activities, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Question**: The question asks for a specific term that describes enzymes with different molecular structures but the same function.

2. **Analyzing the Options**:
- **Option 1: Holoenzymes** - This refers to the complete form of an enzyme that includes its cofactor. This does not fit the description given in the question.
- **Option 2: Isoenzymes** - These are enzymes that catalyze the same reaction but have different molecular structures. This matches the description in the question.
- **Option 3: Apoenzymes** - This term refers to the protein part of an enzyme without its cofactor. This does not apply to the question.
- **Option 4: Coenzymes** - These are organic molecules that assist enzymes in their function but are not enzymes themselves. This does not fit the criteria of the question.

3. **Identifying the Correct Answer**: Based on the analysis, the correct term for enzymes that have different molecular structures but perform identical activities is **isoenzymes**.

4. **Conclusion**: Therefore, the answer to the question is **Option 2: Isoenzymes**.