Which of the following correctly describes the activity or regulation of E coli ribonucleotide reductase?
A)the overall activity of the enzyme is controlled by ATP and dATP
B)the specificity of the enzyme is controlled by all four dNTPs
C)a tyrosine free radical participates in the reaction
D)the reduction is not a result of simple hydride transfer
E)all of the above

Question

Quizplus · Accepted Answer

- Choice A is correct, as the overall activity of E. coli ribonucleotide reductase is controlled by ATP and dATP.
- Choice B is partially correct, as the specificity of the enzyme is mainly controlled by dATP, which inhibits the formation of deoxyribonucleotides other than dATP. However, the other dNTPs can also affect the enzyme activity.
- Choice C is correct, as a tyrosine free radical is involved in the reaction mechanism of E. coli ribonucleotide reductase.
- Choice D is correct, as the reduction involves the transfer of a free radical from a cysteine residue to a tyrosine residue, rather than simple hydride transfer. Therefore, the correct answer is E, all of the above.

Which of the Following Correctly Describes the Activity or Regulation