During chain elongation, peptide bond is formed between carboxyl group of first and amino group of second amino acid by

Options

A. Peptidyl transferase
B. Taq polymerase
C. DNA ligase
D. Helicase

Answer

**Step-by-Step Solution:**

1. **Understanding the Question:**
The question asks about the formation of a peptide bond during chain elongation in protein synthesis. Specifically, it inquires which enzyme facilitates this process between the carboxyl group of the first amino acid and the amino group of the second amino acid.

2. **Identifying the Enzymes:**
The options provided are:
- Peptidyl transferase
- Taq polymerase
- DNA ligase
- Helicase

3. **Analyzing Each Option:**
- **Peptidyl Transferase:** This enzyme is responsible for catalyzing the formation of peptide bonds during the translation phase of protein synthesis. It facilitates the reaction between the carboxyl group of one amino acid and the amino group of another, leading to the elongation of the polypeptide chain.

- **Taq Polymerase:** This enzyme is a DNA polymerase used in PCR (Polymerase Chain Reaction) to amplify DNA sequences. It does not play a role in peptide bond formation.

- **DNA Ligase:** This enzyme is involved in joining DNA strands together by forming phosphodiester bonds. It is not involved in protein synthesis or peptide bond formation.

- **Helicase:** This enzyme unwinds the double-stranded DNA during replication, allowing each strand to be copied. It does not participate in peptide bond formation.

4. **Conclusion:**
Based on the analysis, the correct enzyme responsible for forming the peptide bond during chain elongation is **Peptidyl Transferase**.

**Final Answer:** Peptidyl Transferase

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