Nucleotide Catabolism

1
Nucleotide Catabolism
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Overview of Nucleotide Catabolism

• Ingested nucleotides are not incorporated into
  nucleic acids
• Normal nucleic acid turnover

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Overview

• Importance- rid body of foreign and excess
  nucleotides
• Location- intestine for ingested, liver for own
• Reactions- straightforward
• Energetics- mostly no expense and no gain
• Regulation- not considered

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AMP Catabolism

• Occurs in liver, kidney and small intestine
• First step is cleavage of phosphate group

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AMP Catabolism

• Occurs in liver, kidney and small intestine
• First step is cleavage of phosphate group
• Then deamination occurs

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AMP Catabolism

• Occurs in liver, kidney and small intestine
• First step is cleavage of phosphate group
• Then deamination occurs
• Followed by sugar hydrolysis with phosphate
• Phosphorylysis seen glycogen catabolism

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Xanthine is Oxidized to Uric Acid(decreases
solubility)
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GMP Catabolized by Analogous Pathway, but One
Fewer Oxidations are Required
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Pyrimidines are Catabolized Similarly, but Further

• First deaminated

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Pyrimidines are Catabolized Similarly, but Further

• First deaminated
• then phosphorylized

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Pyrimidines are Catabolized Similarly, but Further

• First deaminated
• then phosphorylized
• and reduced

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Pyrimidines are Catabolized Similarly, but Further

• First deaminated
• then phosphorylized
• and reduced
• and hydrolyzed

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Pyrimidines are Catabolized Similarly, but Further

• First deaminated
• then phosphorylized
• and reduced
• and hydrolyzed
• and hydrolyzed

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Thymine Catabolism Differs Only in Final Product