ʻO nā paʻa disulfide kahi ʻāpana koʻikoʻi o ka hoʻolālā ʻekolu-dimensional o nā protein he nui.Hiki ke loaʻa kēia mau paʻa covalent ma kahi kokoke i nā peptides extracellular a me nā molekole protein.
Hoʻokumu ʻia kahi paʻa disulfide i ka wā e hoʻokumu ai kahi ʻātoma sulfur cysteine i kahi paʻa hoʻokahi covalent me ka hapa ʻē aʻe o ka ʻātoma sulfur cystine ma nā kūlana like ʻole i loko o ka protein.Kōkua kēia mau paʻa i ka hoʻopaʻa ʻana i nā protein, ʻoi aku ka mea i hūnā ʻia mai nā cell.
ʻO ka hoʻokumu maikaʻi ʻana o nā paʻa disulfide e pili ana i kekahi mau ʻano e like me ka hoʻokele kūpono o nā cysteinees, ka pale ʻana i nā koena amino acid, nā ʻano hoʻoneʻe o nā pūʻulu pale, a me nā ʻano hoʻohālikelike.
Hoʻopili ʻia nā peptide me nā kaula disulfide
Loaʻa i ke kino Gutuo kahi ʻenehana apo paʻa disulfide makua.Inā loaʻa i ka peptide hoʻokahi wale nō o Cys, maʻalahi ka hoʻokumu ʻana i ka paʻa disulfide.Hoʻopili ʻia nā peptides i nā ʻāpana paʻa a i ʻole ka wai.
A laila ua oxidized i ka pH8-9 solution.He paʻakikī ka synthesis inā pono e hoʻokumu ʻia ʻelua mau paʻa disulfide.ʻOiai e hoʻopau mau ʻia ka hoʻokumu ʻana o ka paʻa disulfide i ka hopena o ka synthetic scheme, i kekahi manawa ʻoi aku ka maikaʻi o ka hoʻokomo ʻana i nā disulfides preformed no ka hoʻopili ʻana a i ʻole e hoʻolōʻihi i nā kaulahao peptide.ʻO Bzl kahi hui pale Cys, Meb, Mob, tBu, Trt, Tmob, TMTr, Acm, Npys, etc., hoʻohana nui ʻia i ka symbiont.Hoʻolaha mākou i ka disulphide peptide synthesis me:
1. Hoʻokumu ʻia ʻelua mau paʻa disulfide i loko o ka mole a ua hoʻokumu ʻia ʻelua mau paʻa disulfide ma waena o nā mole.
2. Hoʻokumu ʻia ʻekolu mau paʻa disulfide i loko o ka mole a ua hoʻokumu ʻia ʻekolu mau paʻa disulfide ma waena o nā mole.
3. Insulin polypeptide synthesis, kahi i hoʻokumu ʻia ai ʻelua mau paʻa disulfide ma waena o nā ʻano peptide like ʻole.
4. Hoʻohui ʻia o ʻekolu mau ʻāpana o nā peptides i hoʻopaʻa ʻia disulfide
No ke aha he mea kūikawā ka cysteineyl amino group (Cys)?
ʻO ke kaulahao ʻaoʻao o Cys he pūʻulu hoʻoikaika ikaika loa.Hoʻololi maʻalahi nā ʻātoma hydrogen i kēia pūʻulu e nā radical manuahi a me nā hui ʻē aʻe, a no laila hiki ke hana maʻalahi i nā paʻa covalent me nā molekala ʻē aʻe.
ʻO nā paʻa disulfide kekahi ʻāpana koʻikoʻi o ke ʻano 3D o nā protein he nui.Hiki i nā paʻa alahaka Disulphide ke hoʻemi i ka elasticity o ka peptide, hoʻonui i ka ʻoʻoleʻa, a hoʻemi i ka nui o nā kiʻi hiki.Pono kēia palena kiʻi no ka hana olaola a me ka paʻa o ke kūkulu ʻana.He mea nui paha kona pani ʻana no ke ʻano holoʻokoʻa o ka protein.ʻO nā waikawa amino hydrophobic e like me Dew, Ile, Val he mea hoʻopaʻa helix.No ka mea, hoʻokūpaʻa ia i ka disulfide-bond α-helix o ka hoʻokumu ʻana o ka cysteine inā ʻaʻole hana ʻo cysteine i nā paʻa disulfide.ʻO ia hoʻi, inā aia nā koena cysteine a pau i ka mokuʻāina hoʻemi, (-SH, e lawe ana i nā pūʻulu sulfhydryl manuahi), hiki i kahi pākēneka kiʻekiʻe o nā ʻāpana helical.
ʻO nā paʻa disulfide i hoʻokumu ʻia e ka cysteine e paʻa i ka paʻa o ka hale kiʻekiʻe.I ka hapanui o nā hihia, pono nā SS Bridges ma waena o nā paʻa no ka hoʻokumu ʻana i nā hale quaternary.I kekahi manawa ʻo nā koena cysteine e hana i nā paʻa disulfide he kaʻawale loa i ka hale mua.ʻO ka topology o nā paʻa disulfide ke kumu no ka nānā ʻana i ka homology kumu mua o ka protein.Mālama ʻia nā koena cysteine o nā protein homologous.ʻO tryptophan wale nō ka mea i mālama ʻia ma mua o ka cysteine.
Aia ka cysteine i ke kikowaena o ka pūnaewele catalytic o ka thiolase.Hiki i ka Cysteine ke hana i nā acyl intermediates me ka substrate.ʻO ke ʻano i hoʻemi ʻia e hana ma ke ʻano he "sulfur buffer" e mālama ai i ka cysteine i loko o ka protein i ka mokuʻāina i hoʻemi ʻia.Ke haʻahaʻa ka pH, makemake ka equilibrium i ke ʻano -SH i hoʻemi ʻia, akā ma nā wahi alkaline -SH ʻoi aku ka maʻalahi e hoʻoheheʻe ʻia e hana -SR, a ʻo R kahi mea wale nō he hydrogen atom.
Hiki i ka Cysteine ke hana pū me ka hydrogen peroxide a me ka organik peroxides ma ke ʻano he detoxicant.
Ka manawa hoʻouna: Mei-19-2023