Metabolism of protein & amino acids

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

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

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

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

11. b. absorption site mechanism characteristics

13. c. putrefaction concept

14. 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

15. • decarboxylation • reductive & deamination

18. • the sources of ammonia in the intestine

19. 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

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

21. 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

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

24. 2 ) enzymes • L-amino acid oxidase • D-amino acid oxidase • L-glutamate dehydrogenase

26. • characteristics b . transamination 1) reaction

28. 2) important transamination system.

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

30. 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

31. 2) enzyme & coenzyme

33. biological significance & • characteristics

34. c. combined deamination 1) reaction

38. 2) biological significance & characteristics

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

41. 3) characteristics

42. d. nonoxidative deamination • dehydrate deamination • direct deamination

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

45. the detail about the sources of ammonia

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

47. * protein putrefaction

48. *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

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

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