Chuy»ƒn h³a protein 1

download Chuy»ƒn h³a protein 1

of 49

  • date post

    27-Jul-2015
  • Category

    Science

  • view

    875
  • download

    1

Embed Size (px)

Transcript of Chuy»ƒn h³a protein 1

1. Trao i trc tuyn ti: http://www.mientayvn.com/Y_online.html 2. CHUYN HO PROTEIN 3. - Thoi ho protein v nit ca acid amin - Thoi ho b khung carbon ca acid amin - Tng hp acid amin - Chuyn acid amin thnh cc sn phm chuyn bit CHUYN HO PROTEIN 4. S TNG QUT CHUYN HO PROTID Protein thc n Acid amin Protein c th Cc sn phm cha nit khc B khung carbon NH4 + Urea Bi tit Acetyl CoA Pyruvate, sn phm trung gian chu trnh acid citric ATP Glucose 5. THOI HO PROTEIN 6. NHU CU PROTEIN CA C TH - C th cn 30 60 g/ngy (khong 1g/kg/ngy) - Vai tr: Tng hp protein cu trc v chc nng: collagen, myosin Tng hp protein c hot tnh sinh hc: enzym, hormon Tng hp cht c hot tnh sinh hc: histamin, serotonin Cung cp 12% tng nng lng c th ( ng vt n tht 90%) - Acid amin d tha (t thc n) khng c d tr 7. Suy dinh dng nng lng protein: - Th marasmus: suy kit tng qut do thiu c nng lng v protein. - Th kwashiorkor: c trng bng ph, nng lng nhp vo nhng thiu c cht v lng protein. Thc t thng gp dng trung gian ca 2 th ny. 8. NGUN GC ACID AMIN TRONG C TH Acid amin ngoi sinh Acid amin ni sinh 9. TIU HO V HP THU PROTEIN Tiu ho: Proteinase (protease): l cc peptidase thu phn protein thnh peptid ri thnh acid amin t do: - Endopeptidase: ct cc lin kt peptid bn trong chui: pepsin, trypsin, chymotrypsin, thng c hiu cho acid amin - Exopeptidase: ct lin kt peptid u tn Aminopeptidase: u N tn Carboxypeptidase: u C tn Hp thu: Acid amin t do Nim mc rut non Tnh mch ca Gan M, t bo 10. Tiu ho protein Enzym tiu ha c tit ra di dng tin enzym (proenzym) khng hot ng. Khi c a vo ng tiu ho, cc tin enzym s c hot ha thnh dng hot ng. 11. Tiu ho protein Enzym c tnh c hiu, ch ct nhng lin kt nht nh Trypsin: Ct lin kt peptid trc Arg hay Lys. Chymotrypsin : Ct lin kt peptid sau Phe, Trp, Tyr. Ct chm hn sau Asn, His, Met hay Leu. Elastase: Ct LK peptid sau Ala, Gly, Ser, hoc Val. Ti ng tiu ho: -Protein cu (ng vt) c thy phn hon ton. - Protein si (collagen, keratin) c tiu ha mt phn. - Protein ng cc c tiu ha khng hon ton (do lp cellulose). 12. VNG LUN CHUYN PROTEIN Protein c th Acid amin Thoi ho protein Ti s dng tng hp protein Thoi ho ngi ln, 1-2% tng lng protein c th thoi ho mi ngy (ch yu t c), to acid amin t do: - 75-80% c ti s dng tng hp protein mi - 20-25% to urea Protein t bo lun c i mi. Qu trnh thoi ho protein t bo nh enzym catepsin A, B, C trong lysosom ca t bo 13. Cn bng nit (nitrogen balance) ngi trng thnh, khi protein n nh do lng protein tng hp v protein thoi ho lin tc v cn bng. 14. CN BNG NIT L s khc bit gia tng lng nit nhp v tng lng nit mt qua phn, nc tiu v m hi. - Dng: nhp > xut. VD: tr nh ang pht trin, ph n c thai, ngi bnh hi phc. - m: nhp < xut. VD: ngi gi, sau phu thut, ung th tin trin, n khng . Ngi ln bnh thng: nhp = xut 15. THOI HO NIT CA ACID AMIN 16. SN PHM CA THOI HO NIT NG VT - ammonia - acid uric - urea u th ammonia: c xng (Teleostei) (thi nh trao i lin tc vi mi trng nc) u th acid uric: chim (cn gi nc, gi trng lng thp) u th urea: ngi (tan nhiu trong nc, khng c) 17. Acid -amin Acid -ceto -Cetoglutarate L-Glutamate NH3 CO2 Urea Dng di chuyn ca nit trong d ho acid amin (Sinh tng hp urea) Chuyn amin Kh amin oxi ho Chu trnh urea 18. CHUYN AMIN transaminase (vitamin B6) M ng vt: 2 enzyme ph bin nht v hot ng mnh nht l glutamate oxaloacetate transaminase (GOT) v glutamate pyruvate transaminase (GPT) -Cetoglutarate Pyruvate Alanine Glutamate Aspartate Oxaloacetate GPT GOT 19. C CH PHN NG CHUYN AMIN Pyridoxal phosphate ng vai tr gi gc amin tm thi cho c cht k tip (acid ceto) (vit B6) 20. GPT, GOT GPT GOT GPT=glutamate pyruvate transaminase=ALT=alanine transaminase GOT=glutamate oxaloacetate transaminase=AST=aspartate transaminase 21. GOT, GPT - ng dng lm sng Xc nh hot transaminase SGOT (AST) v SGPT (ALT) v ch s GOT/GPT (De Ritis) trong cc bnh l tim, gan hay c vn GOT v GPT l cc enzym ni bo, bnh thng trong huyt thanh < 40 UI/l. Xt nghim trnh v hng cu. Nhi mu c tim: ch yu tng GOT, ch s GOT/GPT > 1, tng gp 2-25 ln, tng sm, cao nht t 16-48 gi. Vim gan siu vi: tng c GPT v GOT; GPT tng nhiu GOT/GPT < 1, tng gp trm ln, sm trc vng da, tng ko di, chuyn thnh mn tnh. 22. KH AMIN OXY HO NAD(P)+ NAD(P)H,H+ L-Glutamate -Cetoglutarat NH3 L-glutamate dehydrogenase L-glutamate dehydrogenase: trung tm ca chuyn ho nit, 75% nit ca protein n vo chuyn ho theo con ng glutamate 23. Amino acid oxidase: m gan, thn Flavin Flavin+H2 H2O2 O2 H2O Acid -amin [Acid -imin] 1/2O2 Acid -ceto H2O NH3 Amino acid oxidase Catalase KH AMIN OXY HO CHNH2 C=NH C=O Tch nhm amin ra khi aa di dnh NH3 pH 7,3, duy nht ch c L glutamate dehydrogenase (L.glu. DH) c CoE l NAD+ c kh nng kh amin trc tip ca L. Glutamate mt cch d dng. Gm 2 giai on xy ra ty th * Giai on 1: Kh hydro nh dehydrogenase (DH) * Giai on 2: Thy phn t pht 24. Kh amin oxy ho DH 25. CHUYN KH AMIN Hu ht cc transaminase c cng c cht v sn phm (glutamate v cetoglutarate) vi glutamine dehydrogenase phi hp gia phn ng chuyn v kh amin bi tit nit cho tng acid amin. Qu trnh ny cho thy vai tr trung tm ca glutamate trong kim sot chuyn ho nit. 26. LIN QUAN GIA KH AMIN V CHUYN AMIN : -Cc enzym kh amin oxyha ca cc acid amin hot ng yu pH 7,3 ngai tr L glutamate dehydrogenase (L.glu. DH) c CoE l NAD+ . -Cc enzym Transaminase ca cc acid amin li ph bin v hot ng mnh c bit Glutamate amin Transferase. - Nn hu ht cc aa c kh amin gin tip thng qua h thng chuyn amin nh CG lm cht trung gian. 27. Chuyn amin Kh amin 28. Kh carboxyl to amin Ph bin vi sinh vt Cc amin khi ht tc dng, s b kh amin v oxy ho: 29. Kh carboxyl to amin 30. Chuyn ch NH3 NH3: Ni sinh: Kh amin oxy ho cc acid amin Thoi ho base nit Ngoi sinh: vi khun c enzym thu phn protein trong rut (NH3/TM ca > NH3/tun hon 5-10 ln) glutamine: Khng c, khng mang in tch, nn d vn chuyn qua mng. L cht vn chuyn NH4 + ch yu/mu Ngun cung cp nhm amin cho tng hp acid amin 31. TNG HP glutamine Mg2+ - Chuyn ch NH3 trong mu. NH3 t do trong mu: 1-2 mg/l - L c ch kh c NH3 ch yu ca no (to urea khng ng vai tr quan trng). Nhng nu NH3 mu cao khng glutamate no tng hp glutamate t -cetoglutarat kit qu cc cht trung gian trong chu trnh acid citric. Glutamine synthetase 32. VN CHUYN glutamine TRONG MU Acid amin NH3 glutamine (60-100 mg/l) NH3 t do (1-2 mg/l) Acid glutamicNH3 NH3 Urea NH4Cl Nc tiu M MU GAN THN 33. Ti gan v thn Ti gan, NH4 + phng thch t glutamin s c tng hp thnh urea v o thi ra nc tiu. Ti thn, thu phn glutamine cho NH4 + to mui amon v o thi theo nc tiu, gip thi H+ thng bng acid-base. Thu phn glutamine/thn tng trong toan mu Thu phn glutamine/thn gim trong kim mu 34. Alanin vn chuyn NH4 + m c cng hot ng mnh l c v gan (chu trnh Glucose-Alanin) 35. Alanine ng vai tr l acid amin quan trng trong tn to ng. 36. NG DNG NH3 tng trong mu gy : Gim pH mu. Tn thng t bo thn kinh NH3 qua hng ro mu no, kt hp glutamate to glutamine gy gim keto glutarat ca no, dn ti gim oxaloacetat, nh hng n chu trnh Krebs, thiu nng lng cho no, tn thng t bo. Tng glutamine trong no, gim d tr glutamate (glu cn thit cho to cc neurotransmitter nh -aminobutyrat (GABA)). Tng glutamine no, thay i cht gy thm thu trong t bo hch glial, gy ph no. 37. NH3 tng trong trng hp: - Suy t bo gan nng: x gan giai on cui, nhim c, nhim virus gy hoi t cp.. - Ni thng ca ch - Di truyn do thiu enzym ca chu trnh urea 38. Chu trnh Urea Chu trnh Ornithin 1932, Hans Krebs Ch yu xy ra gan 5 giai on (1, 2: xy ra trong ty th 3, 4, 5: trong bo tng) N-acetyl glutamate c vai tr iu ho d lp th dng. 39. Chu trnh Urea 1 2 3 4 5 40. Chu trnh Urea 41. Chu trnh Urea CPS I: carbamyl phosphat synthetase OTC: ornithin transcarbamylase 42. CHU TRNH UREA 1: carbamoyl phosphate synthetase 2: ornithine transcarbamoylase 3: arginosuccinate synthetase 4: arginosuccinase 5: arginase 43. Phng trnh tng qut: CO2 + NH4 + + 3ATP + Asp + 2H2O Urea + 2ADP + 2Pi + AMP + PPi + fumarate 44. RI LON CHUYN HO LIN QUAN N CHU TRNH UREA Tng ammonia mu type 1: thiu carbamoyl phosphate synthetase Tng ammonia mu type 2: thiu ornithine transcarbamoylase Tng citrulline mu: thiu arginosuccinate synthetase Tng acid arginosuccinic mu v nc tiu: thiu arginosuccinase Tng arginine mu: thiu arginase trong hng cu Triu chng ca cc bnh l di truyn do khim khuyt mt trong cc enzym ca chu trnh urea thng xut hin ngay sau sinh gm co git, ri lon vn ng, l m, b km, thm ch hn m hay t vong nu khng c pht hin. Nng nht l khim khuyt carbamoyl phosphate synthetase. 45. Urea cycle defects (UCDs) 46. iu ho chu trnh Urea Di hn: thay i ch n protein Lng protein cao, nng enzym tng. Khi ch n protein cn bng, lng enzym gim. Khi i ko di, tng phn hu protein, enzym li tng Ngn hn: N-acetylglutamate l cht d lp th dng ca CPS I. N-acetylglutamate n nh l nh acetyl CoA, glutamate, v arginin Acetyl CoA + glutamate N-acetylglutamate + CoA (Arginin l cht d lp th (+) ca N-acetylglutamate synthetase) N-acetylglutamate synthetase 47. Urea-ng dng lm sng Urea l sn phm thoi ho ch yu t protein, c to thnh t NH3 v ch yu gan. Kh nng to urea ca gan rt ln (tn thng 2/3, kh nng to urea vn bnh thng). Urea c to ra, vo mu, lc thn v thi ra nc tiu. Bnh thng: Urea mu: 3,5 7 mmol/l (0,2 - 0,4 g/l) BUN (blood urea nitrogen) Tng hay gim urea c lin quan mt s tnh trng bnh l. 48. Lin quan gia chu trnh Urea v chu trnh Krebs 49. Lin quan gia chu trnh Urea v chu trnh Krebs