Page 101 - General Biochemistry

Uric Acid
• Uric acid is a product of the breakdown of purine nucleotides
• It is excreted in urine as insoluble crystals.
• High concentration of uric acid (hyperuricemia) can lead gout
Gout :
Gout is one of the most common causes of chronic inflammatory arthritis that is

due to impaired excretion or overproduction of uric acid, Uric acid crystals
precipitate in tissues, mainly joints, kidneys, ureters (stones)
Treatment is done by xanthine oxidase inhibitors that inhibit production of
uric acid ex: Allopurinol which is a hypoxanthine analog that binds to
Xanthine Oxidase to decrease uric acid production
ALLOPURINOL
It is a structural isomer of hypoxanthine that inhibits xanthine oxidase
enzyme by binding to it and forming an irreversible complex

SALVAGE PATHWAY OF PURINES:

It is the recycling of products of nucleic acid break down (from the free bases
adenine and guanine), it occurs in extrahepatic tissues (note that the denovo
pathways occurs in the liver)

It is responsible for 90% of daily purine nucleotide synthesis as salvage
pathways require less energy than that required by denovo synthesis
pathways

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