Question
Which is the product excreted unchanged in catabolism of pyrimidine?
A. Uric acid
B. NH3
C. Pseudouridine
D. Beta alanine
Show Answer
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Correct Answer » C
Explanation
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No human enzyme catalyzes hydrolysis or phosphorolysis of the pseudouridine (ψ) derived from the degradation of RNA molecules.
This unusual nucleotide, therefore, is excreted unchanged in the urine of normal subjects.
Pseudouridine was indeed first isolated from human urine.