25 September 2014

Nucleotide Biosynthesis

Nucleotides are nitrogenous
Our bodies need nitrogen to make nucleotides
Our bodies produce nitrogenous waste when breaking down nucleotides

 - Breakdown of Purines produces Uric acid (a nitrogenous waste)
 - High levels of Uric acid can cause Gout
    - Uric Acid levels are increased when:
       1. Cell turnover is high (some kinds of cancer)
       2. Glucose is being overly-shunted into the Pentose Phosphate Shunt

The nomenclature of Nucleotides changes depending on whether a sugar is attached and if a phosphate is attached.

Two pathways for biosynthesis:
De-Novo (From scratch) – Used in growth
Salvage pathway (Recycling) – Used to maintain
THF is used for nucleotide synthesis by acting as a carbon carrier

Ribose-5-Phosphate from Pentose Phosphate shunt is converted to PRPP, which is converted to phosphoribosylamine
Phosphoribosylamine is converted to IMP
IMP can go down two pathways, making either ATP or GTP

Pyrimidines are formed from Aspartate and Carbomoyl phosphate (same as urea cycle)
 - Then PRPP is added (after the fact)
Carbomoyl Phosphate and Aspartate combine to form the Pyrimidine ring
 - The pyrimidine ring is added to PRPP to form Orotidylate,
- UMP, UTP are formed from Orotidylate
  - CTP is formed from UTP

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