未被消化的蛋白质

1、1Metabolism of protein & amino acids2 A. The physiological & nutritious function of proteins3 nitrogen balance & protein requirement41. nitrogen balance a. concept b. experiment5c. 3 conditions nitrogen equilibriumnegative nitrogen balance positive nitrogen balance62. minimal requirement

2、s of protein3.essential amino acids and their biological value78 an indicator to valuate the nutritional value of the proteins biological value100 的的吸吸收收量量的的保保留留值值蛋蛋白白质质的的生生理理价价值值NN94. Complementary function of proteinsB. Digestion ,absorption,& putrefaction of proteins10diet protein amino acids

3、 digestion Proteolytic enzymea. digestion11 b. absorptionsitemechanismcharacteristics121314c. putrefaction concept15未被消化的蛋白质未被消化的蛋白质,未被未被吸收的氨基酸，肽吸收的氨基酸，肽large intestinebacteriasDecarboxylation deamination有毒；有毒； amine ,H2S indolehydroxybenzene、ammonia（NH3)、other：CO2,CH4NutrimentFatty acid、vitAbsorpti

4、on in intestine excretebloodliver16 decarboxylation reductive & deamination171819 the sources of ammonia in the intestine20blood infiltrateintestine kidney excrete（20g） NH2-CO-NH2 liver NH3 (25%)7g NH2-CO-NH2 urease (bacterias)2NH3+CO2（4g） importance sources of blood ammonia- - absorpted from in

5、testine 21C. general metabolism of amino acids1. Sketch plan2223Dietary proteinTissue protein amination of keto acidsdegradation Synthesis 85% Non essential A.A Digest,absorptiondeaminationamines NH3 keto acidsoxidation Glucose, fatsN.EAAdecarboxylationAmino acid metabolic pool urea other substances

6、242. deamination of amino acids a.oxidative deamination 1) reaction25262 ) enzymes L-amino acid oxidase D-amino acid oxidase L-glutamate dehydrogenase2728 characteristics b . transamination 1) reaction2930 2) important transamination system.31glutamic pyruvic transamination system （glutamic pyruvic

7、transaminase,GPT）（alanine transaminase,ALT）glutamic oxaloacetic transamination systen: （glutamic oxaloacetic transaminase, ,GOT）（aspartate transaminase,AST)32 NH2 O O NH2 Glu 丙酮酸丙酮酸 酮戊二酸酮戊二酸 Ala NH2 CO-COOH O CH-COOH NH2 Glu 草酰乙酸草酰乙酸 酮戊二酸酮戊二酸 ASP COOH-(CH2)2-CH-COOH + CH3-C-COOHCOOH-(CH2)2-C-COOH+CH

8、3-CH-COOHCOOH-(CH2)2-CH-COOH + CH2COOHCOOH-(CH2)2-C-COOH+CH2-COOH ALTAST332) enzyme & coenzyme343536 biological significance & characteristics37 c. combined deamination 1) reaction383940412) biological significance & characteristics42 d. purine nucleotide cycle 1) site 2) reaction43443)

9、characteristics45d. nonoxidative deamination dehydrate deamination direct deamination46473. Metabolism of ammoniaa. the sources of ammonia48 the detail about the sources of ammonia49 protein putrefactionUrea cycle in liver&intestine Absorption in intestine（oxidation of amine ) deaminationBlood a

10、mmonia Ala (liver) Gln sources of blood ammonia 50* protein putrefaction51blood infiltrateintestine kidney excrete（20g） NH2-CO-NH2 liver NH3 (25%)7g NH2-CO-NH2 urease 2NH3+CO2（4g） importance sources of blood ammonia- - absorpted from intestine NH4 excrete from feces*Urea cycle in liver & intesti

11、ne 52 According to the pH in intestine pH NH3 + H+ NH 4+ excrete pH absorpted to venous blood53 protein putrefactionUrea cycle in liver&intestine Absorption in intestine（oxidation of amine ) deaminationBlood ammonia Ala (liver) Gln sources of blood ammonia 54* hydrolysis of Gln55 the fates of am

12、monia produced in renal cellexcrete to the kidney reabsorption to vein blood56 According to renal tube pH pH NH3 + H+ NH4+ excrete pH absorpted to venous blood 57Putrefaction in small intestineIntestine-liver cycle of urea AbsorptionIn small intestine（oxidation of amines）deamination of A.A Ammonia i

13、n blood Ala in liver GLn 58*Ala59 b. The transportation of ammonia synthesis & utilize of Gln materials : Glu , NH3 60 energy: ATP enzyme: Gln synthetase reaction:6162 product: GlnBiological significances,63 glucose-alanine cycle process6465 biological significance66Putrefaction in small intesti

14、neIntestine-liver cycle of urea AbsorptionIn small intestine（oxidation of amines）deamination of A.A Ammonia in blood Ala in liver GLn 67c. the fates of ammonia68Synthesis of non essential A.A or other nitrogen compoundsmuscle or other tissues Glnmuscle ureaNH3 Ala liver69 synthesis of urea-main outl

15、et of ammonia a. site b. process (ornithine cycle )70*肝脏是合成尿素最主要的器官肝脏是合成尿素最主要的器官 血血尿尿切肝犬切肝犬尿素尿素 氨氨尿素尿素用氨基酸饲养切肝犬用氨基酸饲养切肝犬尿素尿素 氨基酸氨基酸尿素尿素 切肾犬切肾犬 急性黄色肝委缩急性黄色肝委缩氨基酸氨基酸尿素尿素 （-） 氨氨尿素尿素 （-）717273This cycle included: 1 overall reaction 2 materials 3 stages 4 steps 5 enzymes74a. materials15NH4Cl NaH14CO3 Fee

16、d dogs14C=O 15NH2 15NH275b. 3 stagesornithine+ NH3+ CO2 citrulline+H20 citrulline+ NH3 arginine+ H20 arginine+ H20 urea+ ornithine 2ATP 1ATP7677NH2 NH2 (CH2)3 C=O + NH3+ CO2 NH + H2O CH NH2 (CH2)3 CH NH2 ornithine citrulline COOH COOH 2ATP78NH2 NH2 C=O NH + NH3 NH + H2O (CH2)3 CH-NH2 COOH Citrullinc

17、 Arginine C=NH (CH2)3 CH-NH2 COOH 1ATP79NH2 C=NH NH +H2O(CH2)3 CH-NH2 COOH Arginine NH2 + (CH2)3 C=O CH-NH2 Orrnithine COOH NH2 NH2 urea80 NH3 （2 molecules） CO2 （1 molecules ） materials urea H2O products OrnithineCitrullinearginine intermediates 81 Intermediate process ( 4 steps, 5 enzymes ) 1) synt

18、hesis of carbomoyl phosphate (mitochondria)8283 NH3+CO2+H2O+2ATP NH2-CO-OPO32-+Picarbomoyl phosphate synthetase 1 84 enzyme carbamoyl phosphate synthetase 1 carbamoyl phosphate synthetase II 85 carbomoyl phosphate carbomoyl phosphate synthetase 1 synthetase IISite mitochondria cytosol source of NH3

19、Gln nitrogenActivator AGA - (N-Acetylglutamic acid )FinalProduct urea pyrimidine 86 synthesis of citrulline (mitochondria) enzyme ornithine transcarbomoylase8788 3) synthesis of arginine (cytosol) enzymeArgininosuccinate synthetase,ASAS Argininosuccinate lyase ASAL ASAS- Key enzyme89904) cleavage of

20、 arginine (cytosol)91929394d. Overall reaction 3ATP+CO2+2NH3 +H2O NH2-CO-NH2 f. summarize95c. Regulation of urea synthesisfoodenzymes (AGA)intermediates9697 biological significant of urea synthesis98Synthesis of non essential A.A or other nitrogen compoundsmuscle or other tissues Glnmuscle ureaNH3 A

21、la liver994. Metabolism of -keto acidsAmino acidNH3AlaGlnureaAmination of a-keto acidsAmination or transaminationTo form non E.A.A.Conversion of fat,glucoseVia TCA cycle oxidized to CO2 & H2O -keto acids100 1) Amination or transamination To form non E.A.A.- ketoglutarate Glu Pyruvate Ala oxaloac

22、etate Asp 101 Glu - ketoglutarate oxaloacetate Asp TCA cycle102 Conversion to lipids or carbohydratesglycogenic amino acid, such as : Ala、Arg、Asp etc（13 ）ketogenic amino acid such as: leu lys (2) glycogenic & ketogenic amino acids such as : Ilu,Phe,Trp,Tye103 TCA cycle is the hinge of metabolism

23、 of lipids , carbohydrates, proteins104*1053) oxidation & provide energy 3. decarboxylation106Amino acids - CO2 -keto acids aminesNon E.A.A Conversion to lipids, carbohydrates TCA cycle- NH3 107 Enzymes & coenzyme some important amines108 -amino butyric acid (GABA） formation109 enzyme functi

24、on metabolic fate110 b. 5-hydroxy tryptamine or ( serotonin）formation111 function c. taurineformation112 function d. histamine formation113e. polyamines formation114115D. metabolism of individual amino acids1. one carbon units116Concept kinds117118 the carrier of one carbon unites -THF 119120 the sources & conversionNH2-CHCOOH +FH4 NH2-CH（CH2）2+N5-CH3-FH4 转甲基酶转甲基酶 （CH2）2 SCH3 SH COOH121122123 function one carbon units & medicine124 metabolism of sulfur- containing amono acidsty