Phezulu, ukwakheka kwamabhondi e-peptide, okukhiqiza ama-dipeptides, kuyinqubo yamakhemikhali elula.Lokhu kusho ukuthi izingxenye ezimbili ze-amino acid zixhunywe ibhondi ye-peptide, isibopho se-amide, kuyilapho iphelelwa amanzi emzimbeni.
Ukwakhiwa kwebhondi ye-Peptide wukwenziwa kusebenze kwe-amino acid ngaphansi kwezimo zokusabela okuncane.(A) i-carboxyl moiety, i-amino acid yesibili (B) I-nucleophilic activated carboxyl moiety bese yakha i-dipeptide (AB)."Uma ingxenye ye-carboxyl (A) ingavikelekile, ukwakheka kwebhondi ye-peptide akukwazi ukulawulwa."Imikhiqizo efana ne-linear ne-cyclic peptides ingase ixutshwe nezinhlanganisela eziqondiwe AB.Ngakho-ke, wonke amaqembu asebenzayo angabandakanyeki ekwakhiweni kwebhondi ye-peptide kumele avikelwe ngendlela ebuyiseleka emuva okwesikhashana ngesikhathi sokuhlanganiswa kwe-peptide.
Ngakho-ke, ukuhlanganiswa kwe-peptide - ukwakheka kwebhondi ngayinye ye-peptide - kuhilela izinyathelo ezintathu zokuhlanganisa.
Isinyathelo sokuqala ukulungisa amanye ama-amino acid adinga ukuvikelwa, futhi isakhiwo se-zwitterionic sama-amino acid asisekho.
Isinyathelo sesibili ukusabela okuyizinyathelo ezimbili ukwakha izibopho ze-peptide, lapho iqembu le-carboxyl le-amino acid evikelwe i-N liqala ukusebenza libe phakathi okusebenzayo bese kwakheka isibopho se-peptide.Lokhu kusabela okuhlanganisiwe kungenzeka njengokusabela kwesinyathelo esisodwa noma njengokusabela okubili okulandelanayo.
Isinyathelo sesithathu ukususwa okukhethiwe noma ukususwa okuphelele kwesisekelo sokuzivikela.Nakuba konke ukususwa kungenzeka kuphela ngemva kokuba wonke amaketanga e-peptide eqoqwe, ukususwa okukhethiwe kwamaqembu okuvikela nakho kuyadingeka ukuze kuqhutshekwe nokuhlanganiswa kwe-peptide.
Ngoba ama-amino acid ayi-10 (i-Ser, i-Thr, i-Tyr, i-Asp, i-Glu, i-Lys, i-Arg, i-His, i-Sec ne-Cys) aqukethe amaqembu asebenzayo we-side chain, adinga ukuvikelwa okukhethiwe, okwenza ukuhlanganiswa kwe-peptide kube nzima nakakhulu.Izisekelo zokuvikela zesikhashana nezihlala unomphela kufanele zihlukaniswe ngenxa yezidingo ezihlukene zokukhetha.Amaqembu okuvikela esikhashana asetshenziswa esinyathelweni esilandelayo ukuze abonise ukuvikelwa kwesikhashana kwe-amino acid noma amaqembu asebenzayo e-carboxyl.Amaqembu okuvikela ahlala unomphela asuswa ngaphandle kokuphazamisa amabhondi e-peptide asevele akhiwe noma amaketanga aseceleni e-amino acid, ngezinye izikhathi ngesikhathi sokuhlanganiswa.
"Ngokufanelekile, ukwenziwa kusebenze kwengxenye ye-carboxyl kanye nokwakheka okulandelayo kwamabhondi e-peptide (ukusabela okuhlangene) kufanele kusheshe, ngaphandle kokwakheka kobuhlanga noma komkhiqizo, futhi ama-reactants e-molar kufanele asetshenziswe ukuzuza isivuno esikhulu."Ngeshwa, azikho izindlela zokuhlanganisa amakhemikhali ezenelisa lezi zidingo, futhi zimbalwa ezifanele ukuhlanganiswa okusebenzayo.
Ngesikhathi se-peptide synthesis, amaqembu asebenzayo ahilelekile ekuphenduleni okuhlukahlukene ngokuvamile axhunyaniswa nesikhungo semanuwali, i-glycine iyona kuphela ehlukile, futhi kunengozi engaba khona yokujikeleza.
Isinyathelo sokugcina kumjikelezo we-peptide synthesis ukususwa kwawo wonke amaqembu okuzivikela.Ukususwa okukhethiwe kwamaqembu okuzivikela kubalulekile ekwandiseni iketango le-peptide ngaphezu kwemfuneko yokususwa okuphelele kokuvikela ekuhlanganiseni kwe-dipeptide.Amasu okwenziwa kufanele ahlelwe ngokucophelela.Ngokuya ngokukhethwa kwesu, i-N ingasusa ngokukhetha i-α-amino noma amaqembu okuvikela e-carboxyl.Igama elithi “isu” lisho ukulandelana kokusabela kokufingqa kwama-amino acid angawodwana.Ngokuvamile, kunomehluko phakathi kokuhlanganisa kancane kancane kanye nokufingqa kweziqephu.I-Peptide synthesis (eyaziwa nangokuthi "i-conventional synthesis") yenzeka ngesixazululo.Ezimweni eziningi, ukunwetshwa kancane kancane kochungechunge lwe-peptide kungahlanganiswa kuphela ngokusebenzisa iketango le-peptide ukuze kuhlanganiswe izingcezu ezimfushane.Ukuze kuhlanganiswe ama-peptide amade, ama-molecule aqondiwe kufanele ahlukaniswe abe izingcezu ezifanele futhi anqunywe ukuthi angakwazi ukunciphisa izinga lokuhlukaniswa ku-C terminus.Ngemuva kokuthi izingcezu zomuntu ngamunye ziqoqwe kancane kancane, inhlanganisela ehlosiwe izohlanganiswa.Isu le-peptide synthesis lihlanganisa ukukhethwa kwesiqephu sokuzivikela esingcono kakhulu nesifaneleka kakhulu, futhi isu le-peptide synthesis lihlanganisa ukukhethwa kwenhlanganisela efaneleke kakhulu yezisekelo zokuzivikela kanye nendlela engcono kakhulu yokuhlanganisa izingcezu.
Isikhathi sokuthumela: Jul-19-2023