| Term | Definition |
|---|
| N- glycosidic | bond between base and sugar in nucleotides |
| N (nitrogen) | C on sugar is always bound to ___ on base |
| phosphate monoester | Bond between sugar and phosphate |
| acid anhydride | bond between phosphates |
| N1 | pyrimidine Nitrogen bonded to sugar |
| N9 | purine Nitrogen bonded to sugar |
| Off 2' | O missing in deoxy sugars |
| A, G, C, & U | nucleotides of RNA |
| A, G, C, & T | nucleotides of DNA |
| hypoxanthine | base of the nucleoside inosine |
| xanthosine | nucleoside of xanthine base |
| ribose - 5- phosphate | starting point for purine synthesis |
| first step of purine synthesis | ribose-5-phosphate => PRPP (phosphoribosyl-pyrophosphate) |
| PRPP Synthetase | ribose-5-phosphate => PRPP (phosphoribosyl-pyrophosphate): enzyme |
| PRPP => 5-phospho-beta-D-ribosylamine | first committed step of purine synthesis |
| PRPP glutamyl amidotransferase | PRPP => 5-phospho-beta-D-ribosylamine: enzyme |
| glycine (step 3) | adds three ring-atoms in purine synthesis |
| inosine monophosphate | first purine ring formed (nucleotide) |
| step 4 (formyl transferase) | step in purine synthesis formyl added |
| adenosine MP | inosine MP - keto, + amino (aspartate) |
| Guanosine MP | inosine MP + IMP dehydrogenase, - keto, + amino (glutamine) |
| IMP, AMP, GMP (@ 1st and 2nd steps) | feedback inhibition of purine synthesis |
| AMP inhibits AMP path and GMP inhibits GMP path | feedback inhibition of purine synthesis at IMP |
| adenosine deaminase | enzyme for adenosine catabolism |
| inosine | product of adenosine deaminase |
| hypoxanthine | product of purine nucleoside phosphorylase in adenosine catabolism |
| guanase | guanine => xanthine: enzyme |
| uric acid | final product of purine catabolism |
| xanthine oxidase | key enzyme in purine catabolism |
| xanthine oxidase | hypoxanthine => xanthine: enzyme |
| xanthine oxidase | xanthine => uric acid: enzyme |
| xanthine oxidase | enzyme deficient in xanthinuria |
| xanthinuria | disorder which can lead to kidney stones |
| Hyperuricemia | excess of uric acid in the circulation and urine. |
| Gout | inflammation of joints due to deposit of sodium urate crystals. |
| PRPP synthetase | mutant form of the enzyme not regulated by phosphate or nucleotides, leads to gout. |
| Glucose-6-phosphatase deficiency | enzyme deficiency leads to increased glucose-6-phosphate leads to increased ribose-5-phosphate via the pentose phosphate pathway, too much uric acid - leads to gout |
| Partial HGPRTase deficiency | enzyme of purine salvage pathway deficiency leads to gout |
| anti-inflammatory (colchicine, ibuprofen etc.) | treatment of gout (symptoms) |
| inhibit xanthine oxidase | treatment of gout 2. |
| Allopurinol | inhibitor of xanthine oxidase. treats gout. |
| probenecid | increase renal clearance of uric acid by inhibiting reabsorbtion. |
| Severe Combined Immunodeficiency Syndrome (SCID), | a deficit of both T and B cells of the immune system, caused by adenosine deaminase deficiency |
| Severe Combined Immunodeficiency Syndrome (SCID), | buildup of dATP which inhibits ribonucleotide reductase and hence DNA synthesis. |
| A deficiency of purine nucleoside phosphorylase can induce this | a deficiency of T-cells, while the B-cells are normal. |
| Antimetabolites | block metabolic pathways by inhibiting enzyme activity. |
| 1. Glutamine analogs 2. Purine nucleotide analogs 3. Antifolates | Antimetabolites that inhibit purine nucleotide biosynthesis: |
| Glutamine analogs e.g. azaserine | inhibit amidotransferases in purine synthesis |
| Purine nucleotide analogs, e.g., mercaptopurine, | inhibit phosphoribosyl-pyrophosphate amidotransferase. |
| methotrexate and aminopterin | Antifolates : folate analogs which inhibit dihydrofolate reductase (DHFR). |
| Antifolates | This inhibition prevents regeneration of formyl tetrahydrofolate required for steps 4 and 10 of purine synthesis. |
| removes sugar, nucleoside => base | function of purine nucleoside phosphorylase |
| guanine | product of purine nucleoside phosphorylase in guanosine catabolism |
Combine with other sets
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