Question

.................... enzyme that catalyzes the transfer of the gamma-phosphate from ATP to the 5'-OH group of single- and double-stranded DNA, RNA, oligonucleotides, and nucleoside 3'-monophosphates.

• A. T4 polynucleotide kinase
• B. Endonuclease
• C. Exonuclease
• D. DNA ligase

Hint:

T4 polynucleotide kinase is often used in molecular cloning and labeling techniques to add a phosphate group to the 5' end of DNA molecules, which is necessary for ligation in some experiments.

Answer 1

The Correct Option is A

The enzyme described in the question is T4 polynucleotide kinase. This enzyme transfers the gamma-phosphate from ATP to the 5'-OH group of single-stranded and double-stranded DNA, RNA, oligonucleotides, and nucleoside 3'-monophosphates. This process is crucial for the phosphorylation of the 5' ends of DNA molecules in molecular biology techniques, such as cloning, labeling, and DNA repair.

(1) Endonuclease: An endonuclease is an enzyme that cuts the phosphodiester bond within a DNA or RNA molecule, rather than transferring a phosphate group.

(2) Exonuclease: An exonuclease removes nucleotides one at a time from the end of a DNA or RNA molecule.

(3) DNA ligase: DNA ligase is an enzyme that joins two DNA strands by forming a phosphodiester bond, but it does not transfer the gamma-phosphate from ATP.

Conclusion: The enzyme that catalyzes the transfer of the gamma-phosphate from ATP to the 5'-OH group is T4 polynucleotide kinase.