End product of Purine catabolism in man

Question

Question

This question was previously asked in

ISRO Pharmacist Previous Year Question paper 2021

Answer 1

Correct Answer: Uric acid

Rationale:

Purine catabolism is the process by which purine nucleotides are broken down into smaller molecules. In humans, the end product of this catabolic pathway is uric acid.
Uric acid is produced when xanthine is oxidized by the enzyme xanthine oxidase. This is the final step in the degradation of purines such as adenine and guanine.
The accumulation of uric acid in the blood can lead to conditions such as gout, where uric acid crystals deposit in joints, causing pain and inflammation.

Explanation of Other Options:

Allantoin

Rationale: Allantoin is the end product of purine catabolism in most mammals, but not in humans. In humans, uric acid is produced instead because humans lack the enzyme uricase, which converts uric acid to allantoin.

Inosine

Rationale: Inosine is an intermediate in the purine catabolic pathway. It is formed from the deamination of adenosine but is further broken down into hypoxanthine and eventually uric acid in humans.

Xanthine

Rationale: Xanthine is also an intermediate in the purine catabolic pathway. It is formed from hypoxanthine and is then oxidized to uric acid by the enzyme xanthine oxidase.

Conclusion:

Among the given options, uric acid is the correct end product of purine catabolism in humans. Understanding the pathway and its intermediates is crucial for diagnosing and treating related metabolic disorders.