Protein denaturation

Conformation (qauv) ntawm lub peptide saw yog kom thiab yog rau txhua protein. Nyob rau hauv tshwj xeeb tej yam kev mob muaj yog ib tug kis loj tus naj npawb ntawm bonds uas tswj cov spatial qauv ntawm cov compound molecule. Raws li ib tug tshwm sim, cov kis kiag li tag nrho cov molecule (los yog ib tug ntau yam pauv loj feem thereof) yuav siv sij hawm rau hauv daim ntawv ntawm random kauj. Qhov no yog hu ua "denaturation". Qhov kev hloov no yuav ua rau muaj mob thaum tshav kub kub ntawm rau caum rau eighty degrees. Yog li, txhua molecule, lub resulting sib tej zaum yuav txawv nyob rau hauv conformation los ntawm lwm yam.

Denaturation ntawm cov nqaijrog yuav siv sij hawm qhov chaw nyob rau hauv tus ntawm tej cov neeg ua hauj peev xwm ntawm kev rhuav tseg tsis-covalent bonds. Qhov no txoj kev yuav tshwm sim nyob rau hauv alkaline los yog acidic tej yam kev mob, nyob rau hauv qhov chaw ntawm lub theem seem, nyob rau hauv qhov kev txiav txim ntawm ib co organic tebchaw (phenols, alcohols thiab lwm tus). protein denaturation yuav tshwm sim nyob rau hauv tus ntawm guanidinium chloride los yog urea. Hais tias cov neeg ua hauj tsim tsis muaj zog bonds (hydrophobic, ionic, hydrogen) nrog carbonyl los yog amino neeg ntawm cov peptide qaum nrog ib tug xov tooj ntawm cov pab pawg ntawm cov amino acid residues, hloov lawv tus kheej muaj protein hydrogen bonds nyob rau hauv lub molecules. Raws li ib tug tshwm sim, ib tug kev hloov tshwm sim nyob rau hauv lub thib ob thiab tertiary qauv.

Kuj mus denaturing agents nyob tsuas yog nyob rau hauv lub xub ntiag nyob rau hauv lub molecule ntawm cov protein tebchaw ntawm disulfide bonds. Trypsin inhibitor muaj peb bonds S - S. Nyob rau hauv lub zwj ceeb ntawm rov qab los ntawm protein denaturation tshwm sim tsis muaj lwm yam pa. Yog hais tias tom qab muab tso rau lub kev twb kev txuas nyob rau hauv tej yam kev mob nyob qhov twg hauv lub oxidation yog nqa tawm SH-pawg ntawm cysteine thiab tsim ntawm disulfide bonds, cov thawj conformation yog rov qab los. Lub xub ntiag ntawm txawm tias ib tug tib disulfide daim ntawv cog lus ho tsub kom lub stability ntawm lub spatial qauv.

protein denaturation, feem ntau nrog los ntawm ib tug txo nyob rau hauv solubility. Ua ke nrog rau qhov no precipitate feem ntau cov ntaub ntawv. Nws tshwm sim nyob rau hauv daim ntawv ntawm "curdled protein." Thaum END ntawm lub tebchaw nyob rau hauv cov tshuaj, "coagulation" undergoes tag nrho cov tshuaj, raws li, piv txwv li, qhov no tshwm sim thaum boiling qe. Thaum denaturation ntawm cov protein loses nws lom ua si. Qhov no txoj ntsiab cai no raws li cov kev siv ntawm carbolic acid (phenol aqueous tov) raws li ib tug antiseptic tshuaj.

Cov khov ntawm lub spatial qauv, lub siab yuav tsis ua hauj lwm nyob rau hauv tus ntawm ntau yam tshuaj mas siv yog ho tsis yooj yim rau cais tawm thiab protein kev tshawb fawb. Tsis tas li ntawd tsim ib co teeb meem thaum uas siv cov tebchaw nyob rau hauv cov tshuaj thiab kev lag luam.

Yog hais tias lub protein denaturation twb nqa tawm los ntawm Raug tus kab mob mus rau high kub, qeeb txias yuav siv sij hawm qhov chaw nyob rau hauv tej yam tej yam kev mob tus txheej txheem renativatsii - rov qab los ntawm cov haiv neeg (thawj) conformation. Qhov tseeb proves hais tias tus tso ntawm lub peptide saw yog nyob rau hauv raws li cov thawj cov qauv.

Cov tsim ntawm lub haiv neeg conformation (qhov chaw qhov chaw nyob) yog ib tug txawj txheej txheem. Nyob rau hauv lwm yam lus, qhov no hnov mus rau lub yam tsawg kawg nkaus tus nqi ntawm free zog muaj nyob rau hauv ib tug qauv. Ib tug yuav raws li ib tug tshwm sim yuav xaus lus tias tus spatial qauv ntawm cov compound yog kho nyob rau hauv lub amino acid ib theem zuj zus nyob rau hauv lub peptide chains. Qhov no nyob rau hauv lem txhais tau tias tag nrho cov polypeptides txog los ntawm alternation ntawm amino acids (piv txwv li, mioglobinovye peptide chains), yuav coj ib tug zoo tib yam zoo.

Cov nqaijrog yuav ua tau qhov sib txawv nyob rau hauv cov thawj cov qauv, txawm tias me me los yog kiag li zoo tib yam nyob rau hauv zoo.