Question 1 of 16
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In tissues that do not carry out active de novo synthesis, maintenance of an adequate supply of adenine nucleotides:
- A. occurs primarily by adenine salvage using A-PRT.
- B. requires ATP uptake from the blood.
- C. depends upon the action of nucleoside phosphorylase
- D. is accomplished entirely by the action of adenylate kinase.
- E. involves hypoxanthine salvage using HG-PRT.
The correct answer is (E).
- A. A-PRT is not considered to be the major enzyme because we produce very little free adenine.
- B. Phosphorylated compounds generally don't cross the plasma membrane.
- C. This enzyme is primarily for the salvage of pyrimidines.
- D. Adenylate kinase equilibrates ATP, AMP and ADP
- E. Correct. The IMP formed is converted to AMP by amination with aspartate.
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Last modified 1/5/95