Question

Uric acid is formed in human from
A. Purines
B. Proteins
C. Glucose
D. Pyrimidines

Answer 1

Uric acid is a heterocyclic compound made of carbon, nitrogen, oxygen, and hydrogen. This forms ions and salts known as urate and uric acid, such as ammonium urate. High uric acid levels in the blood can cause gout and have been linked to other conditions, including diabetes and the formation of uric acid ammonite stones in the kidneys.

Complete answer:
● Besides, living and dead cells break down the nucleic acids adenine (purine) and guanine (purine) into uric acid. Examination of purines and dephosphorylation of purines convert adenine to inosine and guanine to guanosine, respectively.
● The purine enzyme nucleoside phosphorylase converts inosine and guanosine into purine bases, hypoxanthine, and guanine, both of which are converted by oxidation of xanthine oxidase to hypoxanthine and deamination of guanine to xanthine.
● Xanthine is further oxidized to uric acid by xanthine oxidase. Usually, most of the uric acid excretion occurs through the kidneys daily. Humans are unable to oxidize uric acid to the more soluble allantoin compound due to a lack of uricase enzymes.
● In humans, more than half of the antioxidant capacity of plasma comes from hydrogen urination. Most serum uric acid is liberally filtered in the renal glomeruli, and about 90% of filtered uric acid is absorbed, meaning that it plays a significant physiological role. Uric acid is a highly reactive oxygen species (ROS) as well as peroxynitrite and antioxidant

Hence from the above points, it’s clear that the correct option is (A).

Note:
In humans and other higher organism, uric acid (actually a hydrogen urate ion) is the end product of oxidation (decomposition) of purine metabolism and is excreted in the urine, while in most other mammals the uric acid enzyme additionally oxidizes uric acid in the form of allantoin. The loss of uricase in higher primates is associated with the loss of the same ability to synthesize ascorbic acid, which suggests that uric acid may partially replace ascorbic acid in these species. Both uric acid and ascorbic acid are powerful reducing agents (electron donors) and powerful antioxidants.