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Lesson 19
Nitrogen Metabolism 6
Term | Definition |
---|---|
Phenylketonuria (PKU) | Phe cannot be made into Tyr; leads to high Phe and phenylpyruvate, damages nerves. Must be on low Phe diet |
How is cysteine made? | Multistep process from methionine Methionine + ATP --> adenosyl-methionine - CH3 --> adenosyl-homocysteine + H2O --> homocysteine + serine --> cystathionine cleavage yields cystein |
How do our cells get nucleic acids? | from food, salvage of bases, and de novo synthesis |
What is phosphoribosyl-pyrophosphate | PRPP is an activated sugar intermediate necessary for nucleotide synthesis |
Pyrimidine Synthesis: how is carbamoyl phosphate made? | Through CPS -II using Gln, ATP and a NH3 tunnel |
Pyrimidine Synthesis: how is carbamoyl aspartate made? | amino group of aspartate attacks carbonyl of Carbamoyl phosphate |
Pyrimidine Synthesis: how is dihydroorotate made? | -H2O, driven by electron delocalization of product |
Pyrimidine Synthesis: how is orotate made? | With NAD+ absorbing a Hydride ion |
Pyrimidine Synthesis: How is orotate 5'-monophosphate made? | React PRPP --> adds PR part to N |
Pyrimidine Synthesis: How is uridine 5'-monophosphate made? | Removal of CO2 (enzyme increases rate by 10^17) |
How is CTP made? | Gln + ATP through NH3 tunnel replaces C=O on uridine with NH2. |
Human CTP synthase I | used in lipid synthesis |
Human CTP synthase II | used in nucleotide synthesis - activated by GTP |
How is TMP made? | Thymidylate Synthase adds CH3 to uridine |
What does flouro-uracil do? | Potently inhibits thymidylate synthase; used to kill cancer cells |