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Metabolism of purines and pyrimidines - exercise - Vladimíra Kvasnicová.

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Presentation on theme: "Metabolism of purines and pyrimidines - exercise - Vladimíra Kvasnicová."— Presentation transcript:

1 Metabolism of purines and pyrimidines - exercise - Vladimíra Kvasnicová

2 Purine nucleotides a)include an aromatic cycle in the structure b)can contain either adenine or thymine c)include N-glycosidic bond d)are composed of a nucleoside bound to phosphoric acid by an anhydride bond

3 Purine nucleotides a)include an aromatic cycle in the structure b)can contain either adenine or thymine c)include N-glycosidic bond d)are composed of a nucleoside bound to phosphoric acid by an anhydride bond

4 Obrázek je převzat z učebnice: Devlin, T. M. (editor): Textbook of Biochemistry with Clinical Correlations, 4th ed. Wiley ‑ Liss, Inc., New York, ISBN 0 ‑ 471 ‑ ‑ 2 PURINE BASES

5 Obrázek je převzat z učebnice: Devlin, T. M. (editor): Textbook of Biochemistry with Clinical Correlations, 4th ed. Wiley ‑ Liss, Inc., New York, ISBN 0 ‑ 471 ‑ ‑ 2 ribonucleoside deoxyribonucleoside N-glycosidic bond

6 Obrázek je převzat z učebnice: Devlin, T. M. (editor): Textbook of Biochemistry with Clinical Correlations, 4th ed. Wiley ‑ Liss, Inc., New York, ISBN 0 ‑ 471 ‑ ‑ 2 ribonucleotide deoxyribonucleotide ester bond

7 Pyrimidine nucleotides a)include an imidazol ring in the structure b)include thymidine- and cytidine monophosphate c)contain an ester bond d)can include 3 phosphate groups in their structure

8 Pyrimidine nucleotides a)include an imidazol ring in the structure b)include thymidine- and cytidine monophosphate c)contain an ester bond d)can include 3 phosphate groups in their structure

9 Obrázek je převzat z učebnice: Devlin, T. M. (editor): Textbook of Biochemistry with Clinical Correlations, 4th ed. Wiley ‑ Liss, Inc., New York, ISBN 0 ‑ 471 ‑ ‑ 2 PYRIMIDINE BASES

10 Obrázek je převzat z učebnice: Devlin, T. M. (editor): Textbook of Biochemistry with Clinical Correlations, 4th ed. Wiley ‑ Liss, Inc., New York, ISBN 0 ‑ 471 ‑ ‑ 2 ribonucleosides deoxyribonucleoside

11 Obrázek je převzat z učebnice: Devlin, T. M. (editor): Textbook of Biochemistry with Clinical Correlations, 4th ed. Wiley ‑ Liss, Inc., New York, ISBN 0 ‑ 471 ‑ ‑ 2 Ribonucleotides * N-glycosidic bond * ester bond * anhydride bond

12 Purine and pyrimidine nucleotides can be used a)as nucleoside triphosphates for nucleic acid synthesis b)in energetic metabolism of cells c)for activation of metabolic intermediates of saccharides and lipids d)in enzymatic reactions: some coenzymes are nucleotides

13 Purine and pyrimidine nucleotides can be used a)as nucleoside triphosphates for nucleic acid synthesis b)in energetic metabolism of cells c)for activation of metabolic intermediates of saccharides and lipids d)in enzymatic reactions: some coenzymes are nucleotides

14 Synthesis of nucleotides a)uses products of pentose cycle b)includes phosphoribosyl diphosphate (PRDP = PRPP) as a substrate c)needs derivatives of folic acid d)proceeds in a cytoplasm only

15 Synthesis of nucleotides a)uses products of pentose cycle b)includes phosphoribosyl diphosphate (PRDP = PRPP) as a substrate c)needs derivatives of folic acid H 4 –folate (THF) d)proceeds in a cytoplasm only

16 pentose cycle Obrázek je převzat z učebnice: Devlin, T. M. (editor): Textbook of Biochemistry with Clinical Correlations, 4th ed. Wiley ‑ Liss, Inc., New York, ISBN 0 ‑ 471 ‑ ‑ 2 PRPP = PRDP

17 Synthesis of purine nucleotides a)uses ammonia as a nitrogen donor b)proceeds in a cytoplasm c)can start from nucleosides produced by degradation of nucleic acids d)includes uric acid as an intermediate

18 Synthesis of purine nucleotides a)uses ammonia as a nitrogen donor b)proceeds in a cytoplasm c)can start from nucleosides produced by degradation of nucleic acids d)includes uric acid as an intermediate uric acid is the end product of purine ring degradation

19 Obrázek převzat z (leden 2007)http://web.indstate.edu/thcme/mwking/nucleotide-metabolism.html Synthesis of purine nucleotides CYTOPLASMCYTOPLASM

20 Obrázek je převzat z učebnice: Devlin, T. M. (editor): Textbook of Biochemistry with Clinical Correlations, 4th ed. Wiley ‑ Liss, Inc., New York, ISBN 0 ‑ 471 ‑ ‑ 2 AMP GMP IMP

21 Obrázek je převzat z učebnice: Devlin, T. M. (editor): Textbook of Biochemistry with Clinical Correlations, 4th ed. Wiley ‑ Liss, Inc., New York, ISBN 0 ‑ 471 ‑ ‑ 2

22 Synthesis of pyrimidine nucleotides a)starts by the reaction: PRDP + glutamine b)proceeds only in a cytoplasm of cells c)includes orotic acid as an intermediate d)includes inosine monophosphate as an intermediate

23 Synthesis of pyrimidine nucleotides a)starts by the reaction: PRDP + glutamine b)proceeds only in a cytoplasm of cells c)includes orotic acid as an intermediate d)includes inosine monophosphate as an intermediate

24 Obrázek převzat z (leden 2007)http://web.indstate.edu/thcme/mwking/nucleotide-metabolism.html Synthesis of pyrimidine nucleotides CYTOPLASMCYTOPLASM mitochondrion

25 Obrázek je převzat z učebnice: Devlin, T. M. (editor): Textbook of Biochemistry with Clinical Correlations, 4th ed. Wiley ‑ Liss, Inc., New York, ISBN 0 ‑ 471 ‑ ‑ 2

26 enzyme: ribonucleotide reductase + small protein „thioredoxin“ Obrázek je převzat z učebnice: Devlin, T. M. (editor): Textbook of Biochemistry with Clinical Correlations, 4th ed. Wiley ‑ Liss, Inc., New York, ISBN 0 ‑ 471 ‑ ‑ 2 Synthesis of 2-deoxyribonucleotides

27 Obrázek je převzat z učebnice: Devlin, T. M. (editor): Textbook of Biochemistry with Clinical Correlations, 4th ed. Wiley ‑ Liss, Inc., New York, ISBN 0 ‑ 471 ‑ ‑ 2 Synthesis of thymidine monophosphate

28 In a regulation of nucleotide synthesis participate: a)5´-phosphoribosyl-1´-diphosphate (PRDP) b)feed back inhibition c)enzyme carbamoyl phosphate synthetase II (synthesis of pyrimidines) d)enzyme xanthine oxidase (synthesis of purines)

29 In a regulation of nucleotide synthesis participate: a)5´-phosphoribosyl-1´-diphosphate (PRDP) b)feed back inhibition c)enzyme carbamoyl phosphate synthetase II (synthesis of pyrimidines) d)enzyme xanthine oxidase (synthesis of purines) = enzyme of purine degradation

30 Regulation of nucleotide synthesis regulatory enzymeactivationinhibition glutamine-PRPP amidotransferase (purines)  PRPP  IMP, GMP, AMP (allosteric inhibition) carbamoylphosphate synthetase II = cytosolic (pyrimidines)  PRPP  ATP  UTP

31 In a degradation of purine nucleotides a)ammonia is released b)CO 2 is produced c)the enzyme xanthine oxidase participates d)uric acid is produced as the end product

32 In a degradation of purine nucleotides a)ammonia is released b)CO 2 is produced c)the enzyme xanthine oxidase participates d)uric acid is produced as the end product

33 Degradation of purines = „uric acid“

34 In a degradation of pyrimidine nucleotides a)  -amino acids are produced b)the enzyme xanthine oxidase participates c)orotic acid is formed d)ammonia is produced

35 In a degradation of pyrimidine nucleotides a)  -amino acids are produced b)the enzyme xanthine oxidase participates c)orotic acid is formed d)ammonia is produced

36 Degradation of pyrimidines

37 Principal differences between metabolism of purines and pyrimidines purinespyrimidines formation of N-glycosidic bond in 1 st step of their biosynthesis (PRDP is the 1 st substrate) a heterocyclic ring is formed first, then it reacts with PRDP location of biosynthesis cytoplasmcytoplasm + 1 enzyme is in a mitochondrion products of degradation uric acid (poor solubility in H 2 O), NH 3 CO 2, NH 3,  -AMK (soluble in H 2 O)


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