Njikọ Disulfide bụ akụkụ dị mkpa nke nhazi akụkụ atọ nke ọtụtụ protein.Enwere ike ịhụ njikọ ndị a n'ihe fọrọ nke nta ka ọ bụrụ peptides extracellular na protein ụmụ irighiri ihe.
A na-etolite njikọ disulfide mgbe cysteine sulfur atom na-etolite otu njikọ covalent na ọkara nke ọzọ nke cystine sọlfọ atom n'ọnọdụ dị iche iche na protein.Njikọ ndị a na-enyere aka ịkwado protein, karịsịa ndị zoro ezo na sel.
Nhazi nke njikọ disulfide nke ọma na-agụnye ọtụtụ akụkụ dị ka njikwa cysteine nke ọma, nchebe nke ihe fọdụrụ na amino acid, ụzọ mwepụ nke otu nchebe, na ụzọ ijikọ.
A nyadokwa peptide na njikọ disulfide
Akụkụ Gutuo nwere teknụzụ mgbanaka disulfide tozuru oke.Ọ bụrụ na peptide nwere naanị otu ụzọ Cys, nhazi njikọ disulfide kwụ ọtọ.A na-emepụta peptides n'ụdị siri ike ma ọ bụ mmiri mmiri,
A na-emezi ya oxidized na pH8-9 ngwọta.Ngwakọta ahụ dị mgbagwoju anya mgbe ọ dị mkpa ka e mepụta njikọ abụọ ma ọ bụ karịa nke disulfide.Ọ bụ ezie na a na-emecha njikọ nke disulfide n'oge na-adịbeghị anya na atụmatụ sịntetik, mgbe ụfọdụ iwebata disulfides a na-emepụta na-adị mma maka ijikọ ma ọ bụ ịgbatị agbụ peptide.Bzl bụ otu nchekwa Cys, Meb, Mob, tBu, Trt, Tmob, TMTr, Acm, Npys, wdg, ejirila na symbiont.Anyị bụ ọkachamara na peptide disulphide gụnyere:
1. A na-emepụta njikọ abụọ nke disulfide n'ime molecule na ụzọ abụọ nke disulfide na-etolite n'etiti ụmụ irighiri ihe.
2. A na-emepụta njikọ atọ nke disulfide n'ime molecule na ụzọ atọ nke disulfide na-etolite n'etiti ụmụ irighiri ihe.
3. Insulin polypeptide njikọ, ebe abụọ ụzọ abụọ nke disulfide bond na-etolite n'etiti dị iche iche peptide usoro.
4. Njikọ nke ụzọ atọ nke disulfide na-ejikọta peptides
Kedu ihe kpatara cysteinyl amino group (Cys) ji puru iche?
Agbụ akụkụ nke Cys nwere otu na-arụ ọrụ nke ukwuu.Atọm hydrogen dị n'ìgwè a na-adị mfe site na free radicals na ndị ọzọ dị iche iche, ma si otú ahụ nwere ike ịmepụta njikọ nke covalent na ụmụ irighiri ihe ndị ọzọ.
Njikọ Disulfide bụ akụkụ dị mkpa nke nhazi 3D nke ọtụtụ protein.Njikọ Disulphide bridge nwere ike ibelata ngbanwe nke peptide, mee ka isi ike, ma belata ọnụ ọgụgụ nke ihe oyiyi.Mmachi onyonyo a dị mkpa maka ọrụ ndu na nkwụsi ike nhazi.Ndochi ya nwere ike ịdị ịrịba ama maka nhazi protein n'ozuzu ya.Hydrophobic amino asịd dị ka igirigi, Ile, Val bụ helix stabilizer.N'ihi na ọ na-eme ka disulfide-bond α-helix nke cysteine guzosie ike ọbụna ma ọ bụrụ na cysteine anaghị emepụta njikọ disulfide.Ya bụ, ọ bụrụ na ihe niile cysteine residues nọ na mbelata ala, (-SH, na-ebu free sulfhydryl otu), a elu pasent nke helical iberibe ga-ekwe omume.
Njikọ disulfide nke cysteine guzobere na-adịgide adịgide ruo nkwụsi ike nke nhazi ụlọ akwụkwọ sekọndrị.N'ọtụtụ ọnọdụ, SS Bridges n'etiti agbụ dị mkpa maka nhazi nke akụkụ anọ.Mgbe ụfọdụ, ihe fọdụrụ cysteine nke na-emepụta njikọ disulfide dị nnọọ iche na nhazi mbụ.The topology nke disulfide bonds bụ ihe ndabere maka nyocha nke protein isi Ọdịdị homology.A na-echekwa ihe fọdụrụ na cysteine nke protein homologous nke ukwuu.Naanị tryptophan ka echekwara na ọnụ ọgụgụ karịa cysteine.
Cystine dị n'etiti ebe catalytic nke thiolase.Cysteine nwere ike ịmepụta acyl intermediates ozugbo na mkpụrụ.Ụdị mbelata ahụ na-arụ ọrụ dị ka "ihe nchekwa sọlfọ" nke na-eme ka cysteine dị na protein dị na ala dị ala.Mgbe pH dị ala, nha nha na-akwado ụdị -SH dị ntakịrị, ebe na mpaghara alkaline -SH na-adịkarị mfe ka oxidized na-etolite -SR, na R bụ ihe ọ bụla ma e wezụga hydrogen atom.
Cysteine nwere ike imeghachi omume na hydrogen peroxide na organic peroxides dị ka ihe na-egbu egbu.
Oge nzipu: Mee-19-2023