| Question |
Answer |
| Bases |
adenine, guanine, cytosine, uracil, thymine |
| Nucleosides |
adenosine, guanosine, cytidine, uridine, thymidine |
| PRPP |
activates first step of purine synthesis (the commited step); PRPP synthesis is inhibited by purines |
| Glutamine:phosphoribosyl pyrophosphate amidotransferase |
first and commited step of purine synthesis |
| Inosine monophosphate |
parent purine nucleotide |
| Are purines formed on their ribose |
yes |
| Are pyrimidines formed on their ribose |
no |
| Sulfonamides |
inhibit bacterial purine synthesis by inhibiting folic acid synthesis, blocking THF formation |
| Methotraxate |
inhibit dihydrofolate reduction to THF, blocking purine synthesis in humanstrimethoprim |
| Mycophenolic acid |
reversible inhibitor of GMP synthesis; used to prevent graft rejection |
| What two amino acids are used in both purine and pyrimidine synthesis |
glutamine and aspartic acid |
| Carbamoyl phosphate |
first product in pyrimidine synthesis; it’s production is the regulated step |
| CPS II |
carbamoyl phosphate synthetase |
| Orotic acid |
intermediate product in pyrimidine synthesis |
| The enzyme that produces orotic acid is found where in the cell |
mitochondrial membrane (all other enzymes are cytosolic) |
| What’s special about the first three enzymes in pyrimidine synthesis |
different domains on same protein |
| Orotic aciduria |
last two enzymes are different domains of single protein and when this protein is deficient, orotate accumulates |
| Ribonucleotide reductase |
makes DNA’s from RNA’s |
| When in the cell cycle does ribonucleotide reductase function |
S-phase |
| Regulation of ribonucleotide reductase |
each dNTP regulates its own synthesis; dATP inhibits all of them |
| 5-fluorouracil |
suicide enzyme; inhibits dUMP to dTMP synthase |
| thymidylate synthase |
enzyme that converts dUMP to dTMP |
| methotrexate |
inhibits the reduction of DHF to THF in dUMP to dTMP conversion |
| where does degredation of dietary nucleic acids occur |
small intestine |
| what happens to most dietary purines |
converted to uric acid |
| what happens to most dietary pyrimidines |
degraded to highly soluble products |
| diseases associated with purine degredation |
gout, adenosine deaminase (ADA) deficiency |
| gout |
hyperuricemia, doposition of monosodium urate crystals in joints; gouty arthritis; idiopathic; increased risk with lots of meat, seafood, legumes |
| treatment of gout |
anti-inflammatory drugs; allopurinol inhibits urate |
| ADA deficiency |
accumulation of adenosine |
| HGPRT |
enzyme in purine salvage pathway that is deficient in lesch-nyhan syndrome; uses PRPP |
| Lesch nyhan syndrome |
extreme gout; lack of HGPRT enzyme; self mutilation |
| Neurotransmitters |
domapine, norepinephrine, epinephrine, serotonin |
| Epinephrine synthesis pathway |
phenylalanine, tyrosine, dopa, dopamine, norepi, epi |
| MAO |
inactivates catecholamines by degredation along with COMT |
| COMT |
inactivates catecholamines by degredation along with MAO |
| MAO inhibitor |
permits neurotransmitter molecules to escape degredation (used for antidepression) |
| Methylphenidate |
ritalin; blocks dopamine re-uptake; used to treat ADHD |
| Cocaine |
similar actions to methylphenidate |
| Prozac and paxil work by |
blocking serotonin transporter |
Poultry
