Biochemistry : Regulating Nucleic Acid Degradation

Study concepts, example questions & explanations for Biochemistry

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Example Questions

Example Question #1 : Regulating Nucleic Acid Degradation

What is the role of xanthine oxidase?

I. The enzyme xanthine oxidase converts hypoxanthine to xanthine and, also, xanthine to uric acid.

II. Xanthine oxidase is involved in purine (nucleotides like adenine, guanine) degradation.

III. In diseases where there is a high production of purines, the enzyme's products (uric acid) can cause gout.

IV. Gout medication is designed to target xanthine oxidase.

Possible Answers:

II, III, and IV

I and IV

I and II

I, II, and III

I, II, III, and IV

Correct answer:

I, II, III, and IV


Xanthine oxidase is an enzyme important in purine catabolism. Nucleotides from DNA degradation are metabolized to uric acid by xanthine oxidase.In diseases with high levels of nucleotide production, uric acid levels are also high and produce symptoms of gout (uric acid is deposited abnormally in tissues). Gout is treated with inhibitors of xanthine oxidase such as allopurinol, reducing the levels of uric acid and the symptoms of gout.

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