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Catabolism of Purine Nucleotides

S-2-Biochemistry
1 min read

  • The catabolism of purine nucleotides involves the breakdown of nucleotides into their constituent components, ultimately leading to the formation of uric acid.

  • This process occurs mainly in the liver and involves several key enzymes.

Steps in Purine Catabolism

1) Degradation of AMP and GMP

A) AMP Catabolism

  • AMP is deaminated to inosine monophosphate (IMP) by the enzyme AMP deaminase.

  • IMP is hydrolyzed to inosine by the enzyme nucleosidase.

  • Inosine is further hydrolyzed to hypoxanthine by purine nucleoside phosphorylase (PNP).

B) GMP Catabolism

  • GMP is hydrolyzed to guanosine by nucleosidase.

  • Guanosine is converted to guanine by PNP.

  • Guanine is deaminated to xanthine by the enzyme guanine deaminase.

2) Conversion to Uric Acid

  • Hypoxanthine and xanthine are oxidized to uric acid by the enzyme xanthine oxidase.

  • Hypoxanthine is first converted to xanthine and then xanthine to uric acid.

Flowchart of Catabolism of Purine Nucleotides
Flowchart of Catabolism of Purine Nucleotides

Key Enzymes

  • AMP Deaminase

  • Nucleotidases

  • Purine Nucleoside Phosphorylase (PNP)

  • Guanine Deaminase

  • Xanthine Oxidase

Pathway Summary

  • AMP → IMP → Inosine → Hypoxanthine → Xanthine → Uric Acid

  • GMP → Guanosine → Guanine → Xanthine → Uric Acid


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