1. Nucleotide Catabolism

2. Overview of Nucleotide Catabolism Ingested nucleotides are not incorporated into nucleic acids Normal nucleic acid turnover

3. 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

4. AMP Catabolism Occurs in liver, kidney and small intestine First step is cleavage of phosphate group

5. AMP Catabolism Occurs in liver, kidney and small intestine First step is cleavage of phosphate group Then deamination occurs

6. 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

7. Xanthine is Oxidized to Uric Acid (decreases solubility)

8. GMP Catabolized by Analogous Pathway, but One Fewer Oxidations are Required

9. Pyrimidines are Catabolized Similarly, but Further First deaminated…

10. Pyrimidines are Catabolized Similarly, but Further First deaminated… …then phosphorylized…

11. Pyrimidines are Catabolized Similarly, but Further First deaminated… …then phosphorylized… …and reduced…

12. Pyrimidines are Catabolized Similarly, but Further First deaminated… …then phosphorylized… …and reduced… …and hydrolyzed…

13. Pyrimidines are Catabolized Similarly, but Further First deaminated… …then phosphorylized… …and reduced… …and hydrolyzed…

14. Thymine Catabolism Differs Only in Final Product