Inkunga ya disulfide nigice cyingenzi muburyo butatu bwa poroteyine nyinshi.Izi nkunga zishobora kuboneka hafi ya peptide zose zidasanzwe na molekile za poroteyine.
Umubano wa disulfide ubaho iyo atome ya sisitemu ya sulfure ikora umurongo umwe wa covalent hamwe nigice cya kabiri cya atome ya sisitemu ya sulfure ahantu hatandukanye muri poroteyine.Iyi nkunga ifasha guhagarika poroteyine, cyane cyane ziva mu ngirabuzimafatizo.
Gushiraho neza imiyoboro ya disulfide ikubiyemo ibintu byinshi nko gucunga neza sisitemu, kurinda ibisigazwa bya aside amine, uburyo bwo kuvanaho amatsinda arinda, hamwe nuburyo bwo guhuza.
Peptide yashizwemo imigozi ya disulfide
Ibinyabuzima bya Gutuo bifite tekinoroji ya disulfide ikuze.Niba peptide irimo couple imwe gusa ya Cys, gushiraho disulfide guhuza biroroshye.Peptide ikomatanyirizwa mubice bikomeye cyangwa byamazi,
Yahise ihinduka okiside mumuti pH8-9.Synthesis iragoye mugihe hagomba gushingwa ibice bibiri cyangwa byinshi byububiko bwa disulfide.Nubwo gusohora kwa disulfide mubisanzwe birangira bitinze muri gahunda yubukorikori, rimwe na rimwe kwinjiza disulfide byakozwe ni byiza guhuza cyangwa kurambura iminyururu ya peptide.Bzl ni Cys irinda itsinda, Meb, Mob, tBu, Trt, Tmob, TMTr, Acm, Npys, nibindi, bikoreshwa cyane muri symbiont.Dufite ubuhanga muri disulphide peptide synthesis harimo:
1. Ibice bibiri byububiko bwa disulfide bikozwe muri molekile kandi ibice bibiri byububiko bwa disulfide biba hagati ya molekile
2. Ibice bitatu byububiko bwa disulfide bikozwe muri molekile kandi ibice bitatu byububiko bwa disulfide bikozwe hagati ya molekile
3. Synthesis ya insuline polypeptide, aho habaho ibice bibiri bya disulfide ihuza hagati ya peptide itandukanye
4. Synthesis ya joriji eshatu za peptide ya disulfide
Kuki cysteinyl amino group (Cys) idasanzwe?
Urunigi rwuruhande rwa Cys rufite itsinda rikora cyane.Atome ya hydrogène muri iri tsinda isimburwa byoroshye na radicals yubuntu nandi matsinda, bityo irashobora gukora byoroshye guhuza covalent hamwe nizindi molekile.
Disulfide ihuza igice cyingenzi cyimiterere ya 3D ya poroteyine nyinshi.Disulphide ihuza ibiraro irashobora kugabanya ubukana bwa peptide, kongera ubukana, no kugabanya umubare wamashusho.Kugabanya amashusho nibyingenzi mubikorwa byibinyabuzima no gutuza kumiterere.Isimburwa ryarwo rishobora kuba ikinamico kumiterere rusange ya poroteyine.Hydrophobic amino acide nka Dew, Ile, Val ni stabilisateur ya helix.Kuberako ituza disulfide-bond α-helix yo gushiraho sisitemu nubwo cysteine idakora imiyoboro ya disulfide.Nukuvuga ko, niba ibisigazwa byose bya sisitemu byari muburyo bwagabanutse, (-SH, bitwaje amatsinda ya sulfhydryl yubusa), ijanisha ryinshi ryibice byashobokaga byashoboka.
Inkunga ya disulfide ikorwa na sisitemu iraramba kumurongo wimiterere ya kaminuza.Mubihe byinshi, Ikiraro cya SS hagati yinguzanyo zirakenewe mugushiraho ibice bine.Rimwe na rimwe, ibisigisigi bya sisitemu bigize imiyoboro ya disulfide iba itandukanye cyane muburyo bwibanze.Topologiya yububiko bwa disulfide niyo shingiro ryisesengura rya protein yibanze ya homology.Ibisigarira bya sisitemu bya poroteyine za homologique birabitswe cyane.Gusa tryptophan yabitswe cyane kuruta sisitemu.
Cysteine iherereye hagati yikibanza cya catalitiki ya thiolase.Cysteine irashobora gukora acyl ihuza hagati na substrate.Ifishi yagabanutse ikora nka "sulferi buffer" ituma sisitemu iba muri poroteyine muri leta yagabanutse.Iyo pH iri hasi, kuringaniza ishyigikira imiterere -SH yagabanutse, mugihe mubidukikije bya alkaline -SH ikunda kuba okiside kugirango ibe -SR, kandi R nikindi kintu cyose uretse hydrogene atom.
Cysteine irashobora kandi kwitwara hamwe na hydrogen peroxide na peroxide kama nka disoxicant.
Igihe cyoherejwe: Gicurasi-19-2023