Biochemistry : Ligases

Study concepts, example questions & explanations for Biochemistry

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Example Questions

Example Question #1 : Protein Functions

Which of the following correctly mentions the function of a common eukaryotic ligase?

Possible Answers:

Transfer amino groups from an amino acid to an alpha-keto acid

Catalyze the conversion of glucose-6-phosphate into fructose-6-phosphate 

Join lagging strands (Okazaki fragments) of DNA during replication 

Convert adenosine to adenine and ribose in the presence of water

Convert pyruvate into acetyl-coenzyme A

Correct answer:

Join lagging strands (Okazaki fragments) of DNA during replication 


Mammalian DNA ligase I has this function, and there are other DNA ligases which perform it in other animals and eukaryotes (prokaryotes also have their own DNA ligases). All the other functions mentioned are done by other classes of enzymes, not ligases (i.e. hydrolases, aminotransferases, oxidoreductases, etc.).

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