第七章 氨基酸代谢The seventh chapter Amino acid metabolism.docx

1、第七章 氨基酸代谢The seventh chapter Amino acid metabolism第七章. 氨基酸代谢（The seventh chapter. Amino acid metabolism）The seventh chapter is amino acid metabolismMain points of this chapterFirst, the nutritional role of protein1. nitrogen balanceThe total nitrogen balanceThe positive balance of nitrogenThe negati

2、ve nitrogen balance2. essential amino acids and non essential amino acids3. nutritional value and complementation of proteinsTwo. Digestion, absorption and decay of proteinsThree. Deamination of amino acidsAmino acids are mainly removed in three ways, namely oxidative deamination, deamination, and c

3、ombined deamination.Metabolism of four - keto acids1. amino acid into amino acid2. change to sugar or fat3. oxidation energy supplyFive. Metabolism of ammonia1. sources and routes of blood ammonia:The source of blood ammonia: by intestinal absorption; the amino acid deamination of the amino acid ami

4、de; hydrolysis; decomposition of the other nitrogen compounds.The blood ammonia way: in the liver into the synthesis of urea; amino acids; the synthesis of other nitrogenous compounds; the synthesis of asparagine and glutamine; the direct discharge.2. ammonia transport in the bloodThe alanine glucos

5、e cycleThe role of glutamine transport of ammonia3. ornithine cycle and urea synthesisThe characteristics of urea synthesis: synthesis mainly in mitochondria and cytosol of the liver in the synthesis of urea molecules; consume four ATP molecules; the argininosuccinate synthase is a key enzyme in the

6、 synthesis of urea; the two nitrogen atoms of the urea molecule, one from the NH3, a source in ASP amino acid.Six, the decarboxylation of amino acidsCatalyzed by amino acid decarboxylase, coenzyme pyridoxal phosphate, the product was CO2 and amine. Understanding the physiological roles of several im

7、portant amines.Seven, the concept, source and physiological function of one carbon unitEight, S- methionine cycleNine. Metabolism of aromatic amino acidsThe major metabolic processes in nerve tissue cells are phenylalanine, tyrosine, DOPA, dopamine, norepinephrine, norepinephrine, and epinephrine. D

8、opamine, norepinephrine, and epinephrine are collectively called catecholamines. In melanoma cells, Duobake into melanoma. A genetic defect in phenylalanine hydroxylase causes phenylketonuria, a genetic defect in tyrosinase that causes albinism.ExercisesFirst, the multiple-choice question1. the foll

9、owing are the essential amino acids:A. glutamic acid B. phenylalanineC. alanine D. glutamineE. cysteine2. which of the following substances does not belong to a carbon unit?A.CH3 B.CH2C.CH= D.CH=NHE.COOH3. the carrier of a carbon unit in vivo isA. folic acid, B., leucovorinC. dihydrofolate D. pantot

10、henic acidE. biotin4. which of the following is not only the ketogenic amino sugar amino acids?A. leucine B. tyrosineC. isoleucine D. threonineE. glycine5. amino acids that can be converted into taurine are:A. leucine B. aspartateC. valine D. glycineE. cysteine6. the following amino acids that are n

11、ot involved in protein biosynthesis areA. glycine, B. ornithineC. proline, D. arginineE. valine7. which of the following amino acids can produce vasodilators?A.Tryptophan, B., prolineC. glutamic acid D. histidineE. hydroxyproline8. which of the following stages of urea synthesis occurs in mitochondr

12、ia?A. produces citrulline, B. arginine hydrolysisC. produces arginine, D., to produce arginine instead of succinic acidE. or more is wrongWhat kind of substance metabolism does 9.PAPS mainly come from?A. methionine B. taurineC. cysteine D. homocysteineE. or more is wrong10. which of the following tw

13、o kinds of nitrogen does urea come from?A. ornithine and methotrexate phosphateB. aspartic acid and amino formyl phosphateC. - amino - and - amino groups of ornithineD. - amino acids and arginine - amino groups of citrullineE. ornithine - amino and glycine11., the most important metabolic pathway of

14、 ammonia in adults isA. forms the nonessential amino acid B., forming the essential amino acid C., forming NH4 +, which is excreted with urineD. forms urea E., forming purine and pyrimidine nucleotides12. the main cause of elevated blood ammonia isA., excessive intake of protein, B., liver dysfuncti

15、onC. soap water (alkaline) enema, intestinal absorption of ammonia increasedD. renal dysfunction is not more than E.13. which amino acids are produced by the conversion of catecholamines?A. tryptophan, B. glutamic acid, C. aspartate, D. tyrosine, E. lysineThe important role of 14.S- in methionine is

16、A. supplementation methionine, B. synthesis, vitamin C., methylD. produces adenine nucleoside E.Homocysteine synthesisIn the 15. brain, - aminobutyric acid is produced by which of the following metabolites?A. aspartic acid glutamic acid B. C. oxoglutarate D. oxaloacetic acid, E. malic acid16. the am

17、monia produced in the kidneys is mainly derived from ammoniaCombined deamination of A. amino acidsHydrolysis of B. glutamineHydrolysis of C. ureaNon oxidative deamination of D. amino acidsOxidation of E. amines17. the major component of non protein nitrogen in the blood isA. urea, B., uric acid, C.,

18、 creatine, D. polypeptide, E. amino acid18. can the free ammonia be produced by the continuous action of alanine and alpha pyruvate, alanine aminotransferase, and which of the following enzymes?A. B. C. aspartate aminotransferase enzyme glutamate dehydrogenaseD. glutamine synthetase, E., glutaric de

19、hydrogenase19. in the presence of ornithine and amino acyl phosphate, the synthesis of urea also needs to be addedA. arginine, B.HCO3, C., citrulline, D., aspartic acid, E. are not above20. urea cycleThe A. needs to be supplied by the CTPB. aspartic acid contains carbon moieties that are incorporate

20、d into arginineC. arginine is a direct precursor of citrullineD. needs ornithineE. is a direct product of oxaloacetate argininosuccinate.The main route of ammonia in the brain is 21.A. synthesis urea B. diffusion into blood C. synthesis glutamineD. synthesis of amino acids E. synthesis of purine22.

21、which of the following compounds cannot be synthesized from tyrosine?A. thyroxine, B., epinephrine, C.Dopamine, D., phenylalanine, E. melanin23. the main means of deamination of amino acids in muscle isCombined deamination of A.B.L- oxidative deamination of glutamic acidC. ammonia transfer actionD.

22、ornithine cycleE. purine nucleotide cycleWhich of the following 24. kinds of amino acids after transamination can generate oxaloacetateA. glutamic acid, B., alanine, C., threonine, D., aspartate, E., proline25. which of the following substances requires the synthesis of aspartic acid?A. porphyrin B.

23、 steroids C. sphingolipid D. pyrimidine E. coenzyme AWhich vitamin does the coenzyme of 26. transaminase contain?A.Vit.B1, B.Vit.B12, C.Vit.C, D.Vit.B6, E.Vit.D27. which of the following substances is the form of ammonia storage and transportation in the body?A. glutamic acid, B., tyrosine, C., glut

24、amine, D., glutathione, E., asparagine28. which of the following substances is the supplier of sulfate radicals in the body?A.ATP D.FAD E.GMP B.NADPC.PAPS29. albinism is due to deficiencyA. tryptophan hydroxylase, B. tyrosinase, C. phenylalanine hydroxylaseD. proline hydroxylase is no more than E.30

25、. amino acids that can be converted directly to - glutaric acidA. ASP, B., alanine, C., glutamic acid, D., glutamine, E., asparagine31. amino acids that can be converted to acetyl CoA areA. arginine B.Leucine, C., methionine, D., threonine, E., serine32. the enzyme that requires N- acetyl glutamate

26、as an activator in the ornithine cycle isA. formyl phosphate synthetaseB. glutamyl transferaseC. arginine synthetaseD. arginine synthaseE. arginine lyase33. the vitamins necessary for the production of methionine by homocysteine and N5- areA. B. C. D. folic acid dihydrofolate tetrahydrofolate E.N5-

27、methyltetrahydrofolic acid vitamin B1234. what is the lack of enzymes in the liver of people with phenylketonuria?A. phenylalanine hydroxylase B. tyrosinase C. urine black acid oxidaseD. tyrosine aminotransferase E. versus pyruvate oxidaseTwo. Fill in the blanksThe deamination of 1. amino acids has

28、three main ways.2. an enzyme that catalyzes the amino acid reaction of amino acids, said the coenzyme is the latter, which acts in the reaction.3. the simultaneous deamination requires simultaneous participation of two enzymes, the central substance in the reaction being.4. a specific combination of

29、 deamination occurring in muscle tissue is known as the nucleotide involved in the reaction,Finally, the NH3 is removed by the action of an enzyme.5. according to the metabolic transformation of amino acids, 20 amino acids can be divided into, andThree category.6. ammonia is transported mainly in th

30、e blood as well as in two forms.7. the urea formation process is combined with the three carboxylic acid cycle.The basis of the 8. hepatic coma ammonia intoxication theory is the incorporation of ammonia into the brain, resulting in a decrease in brain tissue resulting in reduced ATP production.The

31、product is 9. amino acid decarboxylation, these catalytic reaction of the enzyme, the coenzyme.10. a carbon unit in the body has, andAnd so forth, the carrier of a carbon unit in metabolism is.11. catecholamine include, and, and its formation andMetabolism is closely related.Three. Brief questions1.

32、 combined deamination2. purine nucleotide cycle3. alanine glucose cycle4. ornithine cycleFiveOne carbon unit6. methionine cycle7. - glutamyl cycleFour. Questions and answers1. what are the common pathways for catabolism of various amino acids in the human body? The basic metabolic process is briefly described.2. what is the main metabol