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Metabolism of protein & amino acids PowerPoint Presentation
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Metabolism of protein & amino acids

Metabolism of protein & amino acids

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Metabolism of protein & amino acids

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  1. Metabolism of protein & amino acids

  2. A. The physiological & nutritious function of proteins

  3. nitrogen balance & • protein requirement

  4. 1. nitrogen balance a. concept b. experiment

  5. c. 3 conditions nitrogen equilibrium negative nitrogen balance positive nitrogen balance

  6. 2. minimal requirements of protein 3.essential amino acids and their biological value

  7. an indicator to valuate the nutritional value of the proteins biological value

  8. 4. Complementary function of proteins B. Digestion ,absorption,& putrefaction of proteins

  9. a.digestion digestion diet protein amino acids Proteolytic enzyme

  10. b. absorption site mechanism characteristics

  11. c. putrefaction concept

  12. 未被消化的蛋白质,未被吸收的氨基酸,肽 bacterias Decarboxylation deamination large intestine 有毒; amine ,H2S indole hydroxybenzene、ammonia(NH3)、 Nutriment Fatty acid、vit other:CO2,CH4 Absorption in intestine excrete blood liver

  13. • decarboxylation • reductive & deamination

  14. • the sources of ammonia in the intestine

  15. blood infiltrate intestine kidney NH2-CO-NH2 NH2-CO-NH2 (25%)7g liver urease (bacterias) excrete(20g) NH3 2NH3+CO2(4g) importance sources of blood ammonia----- - absorpted from intestine

  16. C. general metabolism of amino acids 1. Sketch plan

  17. decarboxylation amines Dietary protein Digest,absorption Amino acid metabolic pool degradation Tissue protein Synthesis 85% deamination amination of α—keto acids Non essential A.A α—keto acids NH3 oxidation Glucose, fats N.EAA urea other substances

  18. 2. deamination of amino acids a.oxidative deamination 1) reaction

  19. 2 ) enzymes • L-amino acid oxidase • D-amino acid oxidase • L-glutamate dehydrogenase

  20. • characteristics b . transamination 1) reaction

  21. 2) important transamination system.

  22. glutamic pyruvic transamination system (glutamic pyruvic transaminase,GPT) (alanine transaminase,ALT) glutamic oxaloacetic transamination systen: (glutamic oxaloacetic transaminase, ,GOT) (aspartate transaminase,AST)

  23. ALT COOH-(CH2)2-CH-COOH + CH3-C-COOH COOH-(CH2)2-C-COOH+CH3-CH-COOH NH2O O NH2 Glu 丙酮酸 α—酮戊二酸Ala AST COOH-(CH2)2-C-COOH+CH2-COOH COOH-(CH2)2-CH-COOH + CH2COOH NH2 CO-COOH O CH-COOH NH2 Glu 草酰乙酸 α—酮戊二酸ASP

  24. 2) enzyme & coenzyme

  25. biological significance & • characteristics

  26. c. combined deamination 1) reaction

  27. 2) biological significance & characteristics

  28. d. purine nucleotide cycle 1) site 2) reaction

  29. 3) characteristics

  30. d. nonoxidative deamination • dehydrate deamination • direct deamination

  31. 3. Metabolism of ammonia a. the sources of ammonia

  32. the detail about the sources of ammonia

  33. sources of blood ammonia (oxidation of amine ) deamination protein putrefaction Gln Absorption in intestine Blood ammonia Urea cycle in liver&intestine Ala (liver)

  34. * protein putrefaction

  35. *Urea cycle in liver & intestine blood infiltrate intestine kidney NH2-CO-NH2 NH2-CO-NH2 (25%)7g liver urease excrete(20g) NH3 2NH3+CO2(4g) NH4 excrete from feces importance sources of blood ammonia----- - absorpted from intestine

  36. According to the pH in intestine pH NH3 + H+ NH 4+ excrete pH absorpted to venous blood

  37. sources of blood ammonia (oxidation of amine ) deamination protein putrefaction Gln Absorption in intestine Blood ammonia Urea cycle in liver&intestine Ala (liver)