Question 15 of 16

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Aspartate plays a role in all of the following EXCEPT:

A. conversion of UTP to CTP.
B. de novo synthesis of AMP.
C. de novo synthesis of orotic acid./a>
D. maintenance of the adenine nucleotide pool by a salvage mechanism.
E. the synthesis of most proteins.

The correct answer is (A).

Comments:

A. UTP to CTP does involve an amination but the amino group used is the amide of glutamine.
B. Aspartate provides nitrogen 1 of the purine ring.
C. The whole aspartate molecule (at least the carbons and nitrogen) becomes part of the pyrimidine ring.
D. Maintenance of the adenine nucleotide pool involves salvaging hypoxanthine and then converting IMP to AMP using aspartate.
E. Most, probably all, proteins include aspartate.

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cna

Last modified 1/5/95