purine synthesis.txt

What is the counterion available when phosphate groups are added to nucleosides to make nucleotides?

Mg²⁺
What is one nucleoside that can be used in its nucleoside form and for what?
- Adenosine = promote sleepiness
- Adenosine receptors blocked by caffeine
What do the terms -bis or -tris refer to?

Phosphate groups being attached at different carbons on the nucleotide ring instead of to one another (that would be -di or -tri)
What are the 6 functions of nucleotides? PESICR
- 1) Precursor nucleic acids
- 2) Energy currency (ATP, GTP)
- 3) Second messengers (cAMP)
- 4) Intermediates (UDP-)
- 5) Cofactors (NAD, FAD, SAMe, CoA)
- 6) Ribozymes
What is required for formation of IMP (other than PRPP and Glutamine-PRPP)?
- 1) 6 ATP
- 2) Tetrahydrofolate
What supplies energy to form AMP from IMP?

GTP
What supplies energy for GMP from IMP?

ATP
What percentage of purines are salvaged (recycled)?

90%
Why is the salvage pathway so important (2 reasons)?
- 1) No ATP involved
- 2) Faster (1 step compared to 12 for de novo synthesis)
What pathway forms urea?

Amino acid catabolism
What pathway forms uric acid?

Purine degradation
What percentage of purines are degraded to uric acid?

10% (since 90% are salvaged)
What will happen to uric acid production if the purine salvage pathway drops to 70%?

Purine degradation will rise to 30% b/c of de novo synthesis

Author

kepling

43528

Card Set

purine synthesis.txt

Description

Purine Synthesis

Updated

2010-10-21T19:27:40Z

Show Answers