I-Denaturation yeprotheyini

I-conformation (isakhiwo) se chain peptide iyalwe futhi iyingqayizivele kwiprotheni ngayinye. Ngaphansi kwezimo ezikhethekile, inqwaba yezibopho ziphuka, eziqinisa isimo sendawo ye-molecule ye-compound. Ngenxa yokuphuka, lonke i-molecule (noma ingxenye ebalulekile yalo) ithatha uhlobo lwekhoyili engahlelekile. Le nqubo ibizwa ngokuthi "i-denaturation." Lolu shintsho lungashukunyiswa ngokushisa kusuka emazingeni angamashumi ayisithupha kuya kwangu-80. Ngakho-ke, i-molecule ngayinye etholakala ngenxa yokuphuka ingahluka ngokuvumelana nezinye.

I-denaturation yamaprotheni yenzeka ngaphansi kwethonya lanoma yimaphi ama-agent angakwazi ukubhubhisa izibopho ezingavumelani. Le nqubo ingenzeka ezimweni ze-alkaline noma ezi-acidic, ngaphezulu kokuhlukaniswa kwesigaba, ngaphansi kwethonya lamakhemikhali athile (ama-phenols, ama-alcohols nabanye). I-denaturation yamaprotheni nayo ingenzeka ngaphansi kwethonya le-guanidine chloride noma urea. Lawa ma-agent ahlanganisa izibopho ezibuthakathaka (i-hydrophobic, ionic, i-hydrogen) neqembu le-carbonyl noma lama-amine we-peptide backbone kanye namaqembu amaningi ama-amino acid radicals, esikhundleni sezingxenyana ze- hydrogen ezikhona ngaphakathi kwiprotheni ngaphakathi kwe-molecule. Ngenxa yalokho, kukhona ushintsho esakhiweni sesibili nesisemfundo.

Ukumelana nesenzo sokwehlisa ama-agent kuncike ekutheni kube khona izibopho ze-disulfide ku-molecule ye-protein eklasini. I-trypsin inhibitor inezibopho ezintathu ze-S-S. Ngaphansi kokuncishiswa kwabo, amaprotheni denaturation kwenzeka ngaphandle kwamanye amathonya. Uma, ngemuva kwalokho, le nhlanganisela ifakwa ezimweni lapho ukhiqizwa kwamaqembu e-SH we-cysteine kwenzeka futhi ukwakheka kwezibopho ze-disulfide kwenzeka, khona-ke ukuhlanganiswa kokuqala kuzobuyiselwa. Kulesi simo, ukutholakala kwesinye isibopho esivumelwaneni kakhulu kukhulisa ukuqina esimweni sendawo.

I-denaturation yamaprotheni, njengombuso, ihambisana nokunciphisa ekuziphatheni kwayo. Ngesikhathi esifanayo, kuvame ukwakhiwa. Kubonakala ngesimo se-"squirrel ekhishwe". Uma ukuhlanganiswa kwezimboni kulesisombululo kuphezulu, "ukugcoba" kulandela isisombululo sonke, njengokuthi, uma upheka amaqanda ezinkukhu. Uma i-denatured, iphrotheni ilahlekelwa umsebenzi wayo wezinto eziphilayo. Lesi simiso sisekelwe ekusetshenzisweni kwe- carbolic acid (isisombululo sama-phenolic esiphundu) njengesifo se-antiseptic.

Ukungahleleki kwesakhiwo sendawo, amathuba amakhulu okubhujiswa ngaphansi kwethonya lama-agent ahlukahlukene, okwenza kube nzima kakhulu ukuhlukanisa nokufunda amaprotheni. Izinkinga ezithile nazo zidalwe uma usebenzisa amakhemikhali embonini nasemithi.

Uma i-denaturation yeprotheni yenziwa ngokuboniswa kwamazinga aphezulu okushisa, bese kuthi ngaphansi kokupholisa kancane kancane, ngaphansi kwezimo ezithile, inqubo yokuvuselelwa iyenzeka-ukubuyiswa kokuhlanganiswa komdabu (kokuqala). Leli qiniso lifakazela ukuthi ukufakwa kochungechunge lwe-peptide kwenzeka ngokuvumelana nesakhiwo esiyinhloko.

Ukwakhiwa kwesimo sokuzalwa komuntu (indawo yokuqala) inqubo yokuzikhethela. Ngamanye amazwi, leli lungiselelo lihambelana nesilinganiso esincane semandla mahhala afakwe kule molekyuli. Ngenxa yalokho, kungaphetha ngokuthi isakhiwo sendawo yenkimbinkimbi sibhalwe ngokulandelana kwe-amino acid emaketangeni e-peptide. Lokhu, kusho ukuthi zonke izinhlobo ze-polypeptides ezifana nokulandelana kwe-amino acid (isb., Izinyathelo zamaphethini ze-myoglobin) zizothatha ukufana okufanayo.

Amaprotheni angaba nokungafani okuphawulekayo esakhiweni esiyinhloko, noma ngabe kukhona okufana noma okufanayo ngokuvumelana.