Hoa Hoc Protid

5/26/2018 Hoa Hoc Protid

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HOA HOC PROTID


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MUC TIEU BAI HOC Viet cong thc cua 20 acid amin thng gap

trong phan t protein

Trnh bay c cac tnh chat cua acid amin: tnhtch ien, tnh chat vat ly va hoa hoc Neu c ten mot so peptid co chc nang sinh

hoc Trnh bay c cac lien ket va cac bac cau truc

cua protein Trnh bay c cac tnh chat cua protein: khuech

tan, tch ien, hoa tan va ket tua, bien tnh.


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PROTEIN LA G?

Proteinla ai phan t polymer do cac phan tacid amin(monomer) noi vi nhau banglien

. quyet nh.

Protein co nhieu chc nang the hien trongcac vai tro: cau truc, xuc tac, van chuyen,van ong, dinh dng va d tr, bao ve, ieuhoa hoat ong cua c the.


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PROTEIN

Acid amin (-amino acid) Peptid Protein

PROT


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ACID AMIN Cau truc Acid amin

*mot nhom amin (-NH2)

-cung gan vao carbon *mot chuoi ben (-R).

Acid amin c ve

*- N ben trai*- C=O ben phai

Goc R


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ACID AMIN Cau truc

-Amino acid


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ACID AMIN Cau truc Trong thien nhien co khoang 300 AA Trong protein/sinh vat co 20 AA

(o la cac -amino acid) Mot so AA khong phai la -amino acid:-alanin, -aminobutyric acid


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ACID AMIN ong phan

Tr glycin, tat ca AA

bat oi

(Carbon nam v tr

trung tam bat oi )


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ACID AMIN ong phan

Trong protein ch cha L--amino acid


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ACID AMIN ong phan

D, L da vao D- va L- glyceraldehyd(L: levorotatory; D: dextrorotatory)


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ACID AMIN Phan loai

Da vao chuoi ben (-R) Khong phan cc Phan cc va khong tch ien Phan cc va tch ien


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ACID AMIN Phan loai

AA khong phan cc hydrophobic water fearing


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ACID AMIN Phan loai

AA khong phan cc hydrophobic water fearing


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ACID AMIN Phan loai

AA phan cc khong tch ien(chuoi ben cha cac nhom phan cc kho ion hoa)


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ACID AMIN Phan loai

AA phan cc khong tch ien(chuoi ben cha cac nhom phan cc kho ion hoa)


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ACID AMIN Phan loai

AA phan cc va tch ien am pH c the(chuoi ben cha nhom carboxyl)


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ACID AMIN Phan loai

AA phan cc, tch ien dng pH c the(chuoi ben cha nhom amin)


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ACID AMIN Phan loai

Mot so AA ac biet

Hydroxylysine, hydroxyproline -collagen

-Carboxyglutamate -prothrombin

3-Monoiodotyrosine, 3,5-diiodotyrosine, T3, T4 -

hormon giap trang va cac tien chat Citrullin, ornithin -sinh tong hp ure


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ACID AMIN Phan loai

Vai tro cua (R)/AA trong chuoi polypeptid

Vong imidazole (His, trong Hb, Mb)

Chc OH (Ser, Thr), SH (Cys)

Cysteine-SH HS-Cysteine Cysteine-S-S-CysteineCOO-,NH3+ cua (R) cac AA acid hay base

ong vai tro quan trong trong hnh thanh cau truc, thamgia cac nhom trung tam hoat ong cua enzym


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ACID AMIN Phan loai

Vai tro cua cac AA trong chuoi polypeptid

AA k nc khong tng tac trong moi trng

,protein. Loai nay khong b ion hoa, khong tao LKhydro.AA a nc tng tac vi moi trng nc, tao

LK hydro vi nc va chiem t le ln tren bemat ngoai cua protein, hay co mat cac trung tamhoat ong cua enzym.


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ACID AMIN ien tch pH trung tnh, AA dang lng cc


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ACID AMIN Tnh chat

pH trung tnh (pH mau: 7,4; pH noi bao: 7,1)

Dipolar (zwitterion)


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ACID AMIN ien tch

R-COOH R-COO- + H+

R-NH3+ R-NH2 + H+

Theo quan niem Bronsted th AA cha tnhat 2 nhom acid phan ly yeu

AA la acid yeu co the phan ly nhieu lan


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ACID AMIN ien tch


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ACID AMIN Tnh chat Dang ion hoa cua AA thay oi tuy theo pH moi

trng thay oi [C] cua cac dang ion Tai pH moi trng:

o A+/- = MAXo A- = A+ = MINo IEN TCH = 0

AA khong di chuyen trong ien trng

pHi(isoelectric)(pH ang ien)


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ACID AMIN Tnh chatTai pH moi trng < pHi

AA hoat ong nh base

- - - - -NH3+ NH3+

Ton tai ca 3 dang ion A+/-, A- , A+

Cation A+ chiem t le nhieu nhatTrong ien trng, AA chuyen ve cc (-)

H+


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ACID AMIN Tnh chatTai pH moi trng > pHi

AA hoat ong nh acid

- - - - - -NH3+ NH2

Ton tai ca 3 dang ion A+/-, A- , A+

Anion A- chiem t le nhieu nhatTrong ien trng, AA chuyen ve cc (+)

H+


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ng chuan o glycin 0,1M, 25oC

pK1 - COOH

pK2 - NH3

+


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ACID AMIN Tnh pI


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ACID AMIN Tnh chat

Acid aspartic

A+ A+/- A+/-/- A-/-

p 1 p 2 p 3

Arginin

A+/+ A+/+/- A+/- A-

pK1 pK2 pK3


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ACID AMIN Tnh chat


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Tnh chat vat ly

De tan trong dung moi phan cc

ngot kieu am)

Pho hap thu:


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Tnh chat vat ly

Cac acid amin khong hap thu anh sang nhn

,Phe, Tyr, His va Trp) hap thu anh sang vungtia hong ngoai Ch Phe, Tyr, His va Trp hap thu vung UV o nong o AA tot nhat 280 nm ng dung: dd acid amin, nc mam


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Tnh chat vat ly


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Tnh chat hoa hoc

PHAN NG DO NHOM -NH2 VA -COOH

1. Phan n NINHYDRIN


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2. PHAN NG TAO LIEN KET PEPTID


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PEPTID

Ten: Acid glutamic - Glycin - Alanin - LysinK hieu ba ch: Glu-Gly-Ala-LysK hieu mot ch: EGAK


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PEPTID - Cau tao


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PEPTID

C

O

N

H

Lien ketPEPTID

AA1 AA2 AA3 AA4

(Ban chat la LK amid)


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PEPTID

Vi n AA, co n-1 lien ket peptid

Co 2 au: N tan va C tan

N tan pha ben trai - au chuoi

C tan pha ben phai - cuoi chuoi

Ten goi theo ten rieng Glutathion, glucagon, insulin,ACTH


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PEPTID- tnh chat

Phan t peptid co:

Nhom -amin t do au N tan

Nhom -carboxyl t do au C tan

Bo khung: mach lien ket peptid

Chuoi ben: cac goc R cua cac AA

Co tnh chat lng tnh giong AA


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PEPTID- tnh chat

Moi phan t peptid co mot pHitng ng

pH moi trng > pHi:Peptid tch ien (-)

pH moi trng < pHi:Peptid tch ien (+)

Phan ng nhan biet lien ket peptid (Biuret)

OH-, Cu++Phc tm hongBiure

(-CO-NH- )


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PEPTID- tnh chat

-NH3

OH-

Cu++

Phc tm hongBiure


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PEPTID- tnh chat

Tng t vi protein Peptid co t 3 AA (2 lien ket peptid) th phan ng biuret (+)


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PEPTID co hoat tnh sinh hoc

Neuropeptid: Co mat nao bo, anh hng lenhoat ong cua TKTW, chu yeu do tuyen yen va vungdi oi.

Enkephalin (5AA), endorphin (15AA); oxytocin

Hormon peptid:

Insulin (51AA); glucagon (29AA); gastrin (16AA)

Peptid khang sinh:do vi khuan, nam tao ra; cha ca

L va D AA; cha mot so AA khong co trong protein


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Gramicidin S: Val-Orn-Leu-D.Phe-Pro

Pro-D.Phe-Leu-Orn-Val

,phospholipid cua vi khuan.

Peptid tham gia he thong oxy hoa-kh

Glutathion: glutamyl-cystein-glycin

2 G-SH 2 G-S-S-G-2H+2H


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PROTEIN: Phan loai

Nhieu he thong phan loai do s phc tap ve

a u tru c Tnh chat ly hoa hc nang sinh hoc

Da vao hnh dang:Protein si (collagen, elastin);

Protein cau (enzym, alb, myoglobin)

Da vao chc nang: Cau truc, van chuyen, xuc tac Da vao tnh chat vat ly: phan biet cac protein gan nhau

LP (chylomicron, VLDL, LDL, HDL)


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PROTEIN: Phan loai


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PROTEIN: Phan loai

Protein huyet thanh: Albumin, globulin (1,2,,)

Da vao tnh chat hoa hoc:

Protein thuan: ch cha cac AA

Albumin: pHi 4,6-4,7 MW 35.000-70.000

Globulin:pHi 5,2-6,8 MW 90.000-150.000

Histon: pHi 9-11, cha nhieu AA baseKeratin: MW >2trieu Cha nhieu cystin

Collagen: thuy phan tao gelatin; MW 350.000


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PROTEIN: Phan loai

Protein tap(protein thuan + nhom ngoai)

Nucleoprotein

Cromoprotein Lipoprotein

Glycoprotein


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PROTEIN-Lien ket

Ban chat la LK amid (LK peptid hi ngan hn LK n khac).

Tnh chat LK oi mot phan, han che quay quanh LK

Lien ket peptid

peptid, nen 4 nguyen t CO-NH- nam tren cung mot

mat phang


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PROTEIN-Lien ket peptid

LK peptid khong quay

- -va (-CO-C -)(Psi)quayt do


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Chuoi polypeptid c coi la co nhieu matphang, co 2 goc quay gia moi mat phang


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V anh hng khong gian, Phi va Psi quay han che taocau hnh Trans > Cis tao cau truc khong gian protein


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PROTEIN-Lien ket disulfid

LK ong hoa tr gia 2 cystein tren 1 chuoi hay 2

chuoi khac nhau.

ong vai tro quan trong trong duy tr cau truc bac III Khi muon phan tch protein phai pha v LK nay

cystein cystein

S S

cystein

cystein

SS


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PROTEIN-Lien ket Hydro

La lc hut tnh ien gia H tha ien tch (+) va O(hay N, Cl) tha ien tch (-) tren cung chuoi hay cacchuoi khac nhau. Trong protein, so lng LK hydro ln.

0xy

H

Quan trong trong hnh thanh va duy tr cau truc bac II


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PROTEIN-Lien ket ion

La lc hut tnh ien gia nhom COO- (Glu, Asp)vi NH3+ (Lys, Arg), con goi la LK muoi

Glu

Lys

COO-

NH3+


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PROTEIN-Tng tac k nc gia cac R

Tng tac gia cac goc khong phan cc ben trongprotein (lien ketVan der WAAls): yeu, khong la lien

.

alanin

valin

R

R


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PROTEIN-Lc Van de Waals

La lc tng tac gia cac nguyen t, phan t

khoang cach ngan

cc ky yeu


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PROTEIN-Vai tro cua cac LK

Cac AA noi vi nhau bang lien ket peptid tao nenchuoi polypeptid.

Trnh t cac AA la mot dang thong tin quyet nh

cau truc cua protein.Cac tng tac khong hoa tr (thuoc goc R) ongvai tro quan trong trong cau truc cua protein.Cac AA lien ket vi nhau bang cac lien ket co o

linh hoat gii han e tao nen cau truc ong hoc 3chieu cua phan t protein.

Chnh cau truc se quyet nh chc nang cua protein


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PROTEIN-cau truc

Vao nhng nam 1950, Linus Pauling at ten chonhng cau truc ong tm ra nh nhieu xa tia X la xoan

a p a, a gap e a. Nay them mot so cau truc khac nh uon beta, cautruc collagen


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PROTEIN-cau truc bac 1

Bieu th trnh t cac AA trong chuoi polypeptid

V tr cua caccystein kha nang tao LKdisulfid


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Bieu th s tng quan cua cac AA gan nhau trong

chuoi polypeptid

Lien ket hydro ong vai tro quan trong Ba dang cau truc bac 2 thng hay gap

Xoan (Alpha helix)

La gap (Beta-Pleated Sheet Cau truc uon ( turns)


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PROTEIN-xoan Cau truc hnh roi, si polypeptid xoan quanh truc

phan t tao phan loi, goc R cua AA nho ra ngoai

Ben vng nh LK hydro, moi vong xoan co 3,6 AA Protein nhieu xoan

(Hb, Mb)

Protein t xoan

(Chymotrypsin)


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PROTEIN-xoan


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PROTEIN-xoan


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PROTEIN-La gap

Chuoi polypeptid trai ra co hnh zigzag

Chuoi polypeptid ke ben khac chieu:oi song

C cau ben la do lien ket hydro gia cac chuoi

peptid bac I xa nhau


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PROTEIN-La gap


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i song Song song


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PROTEIN-La gap


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PROTEIN-La gap

A v B: i song; B v C: song song


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PROTEIN-La gap


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PROTEIN-Cau truc bac 2 khac

Cau truc uon : cho phep xon va la gap sap xep

side-by-side (prolin va glycin)


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PROTEIN-Cau truc bac 2 khac

Xoan collagencha nhieu glycin, prolinva hydroxyprolin tao

dang ba si gn vi nhaunh LK hydro.


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Cau truc khong gian 3 chieu trong 1 chuoi PP.Co ac iem:

o cac cau ruc ac g ong ay ac n auCuon lai tao thanh khoi ac chacLK disulfid ong vai tro quan trong trong

duy tr cau truc nay


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Co t 2 chuoi polypeptid bac 3 tr len, tao thanhproteinoligomer. Tng chuoi PP c goi la

, , , .Cac chuoi PP lien ket vi nhau qua cac lc

khong ong hoa tr: lien ket H va lien ket tnhien.

MW cua hau het cac protein bac 4 >50.000 Da.


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Hemoglobin (Hb) gom 4 tieu n v:2 chuoi , 2 chuoi


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PROTEIN

Ch thay oi 1 AA trong phan t protein dan ti thayoi hoat tnh hay chc nang cua protein o.

HbA: X-X-X-X-X-Glu (chuoi )

HbS: X-X-X-X-X-Val(chuoi )

lam thay oi hnh dang cua hong cau t hnh da thanh

hnh liem, giam tnh an hoi va tang kha nang v hongcau


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PROTEIN HC hnh liem


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PROTEIN-Tnh chatLy tnhProtein/nc tao dd keo (1


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PROTEIN-Tnh chat

Ap dung:

an n an ao Tham phan phuc mac


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PROTEIN-Tnh chat Protein/nc tao ap suat (p) tham thau goip keo

P keo ASK ASTT < ASKASTT = ASK

40 28 16 4090%

10%Bach huyet


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PROTEIN-Tnh chat Tnh chat acid-base

Giong AA va peptid, protein/ddch ton tai ca 3dan ionP+/- P+ P-.Tu H moi trn so vi Hcua protein ma protein tch ien(+)hay(-)

ng dung ien di protein (electrophoresis)

NT:da tnh chat tch ien pH mt pHi

di chuyen trong ien trng ien tch

Trong lngKch thc


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PROTEIN-Tnh chat ien di o

Proteinhuyet thanh(serum)

Alb: pHi 4,6 5,2Globulin: pHi 5,2- 6,8


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PROTEIN-Tnh chat

Hoa tan va ket tua

Dd keo ben vng nh

Lp ao nc (hydrat hoa)S tch ien cung dau

pH

Nong o muoi :muoi trung tnh

Nong o muoi thap:tang o tan(salting in)Nong o muoi cao:giam o tan, co the gay

tua protein(salting out)

pH = pHi: o tan thap nhatpH pHi: o tan gia tang


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PROTEIN-Tnh chatng dung

Phng phap diem tch: loai muoi khoi dd proteinTua globulin: muoi amoni sulfat ban bao hoa Dung moi:Alcol, ceton, amoni sulfat giam o tan

Nhiet o: 0oC en 40oC: o tan tang

>40oC: o tan giam, mat tnh ben vng

Tua globulin: muoi amoni sulfat ban bao hoaTua albumin: muoi amoni sulfat bao hoa


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PROTEIN-Tnh chat S bien tnh cua protein

Protein Bien tnhTo, pH, chat tayAcid manh, kim loai nangcid manh, kim loai nang

Cau truc b ao lon

Ch con lien ket peptid

Goc k nc (R) quay ra ngoai

Tnh chat ban au b mato tan giam, mat tnh sinh khang nguyen

Mat hoat tnh sinh hoc, de tieu hoa

PROTEIN


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PROTEIN-Tnh chat

S bien tnh thuan nghch

Trong mot so ieu kien nhat nh, rotein b bien tnh co the

tr lai dang ban au vi cautruc, tnh chat va chc nangnguyen thuy

Th du: ribonuclease


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PROTEIN-Tnh chat S bien tnh khong thuan nghch

khong tr lai trang thai ban au

ng dung

Chiet xuat, tinh che protein (enzym) ephong s bien tnh (thao tac to lanh, am baopH)

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Hoa Hoc Protid