Unxibelelwano lwePeptide

Umxholo

• Iipropati
• Imizekelo yeebhondi zepeptidi

Ithiyiwe iibhondi zepeptidi kuhlobo oluthile lwe unxibelelwano phakathi kwe-amino acid kunye nenye, eyenzeka kwiqela le-amino (-NH₂) kwi-amino acid yokuqala kunye neqela le-carboxyl (-COOH) okwesibini, ukuvelisa ukudibana kwe-CO-NH kunye nokukhulula imolekyuli yamanzi.

Ngale ndlela imolekyuli entsha ibizwa Ipeptide kwaye oko kuya kuthiywa ngegama zombini iiamino acid. Ke, ubudlelwane be peptide phakathi kwemolekyuli ye kwintombazana (ibonelelwe sisikhululo se-NH) kunye nenye evela iseli (ebonelela nge-CO-terminal) iya kuthiwa yi-alanyl-serine peptide.

Le yenye yeendlela zokubopha oko vumela iiamino acid ukuba zidityaniswe (ngokuphelelwa ngamanzi emzimbeni) ukuvelisa izakhiwo ezintsonkothileyo (iipolypeptides)Ukusukela ukuba nje ukuba ikhonkco lifunyenwe, kunokwenzeka ukuba uqhubeke nokujoyina iiamino acid ngenkqubo efanayo, ukuqala kwiqela lasimahla lehydroxyl. Yinkqubo eqhelekileyo kakhulu kwi izinto eziphilayo.

Iipropati

Ezi ntlobo zonxibelelwano zineempawu ezithile. Njengokuba, ikhonkco elimiselweyo lilula, kodwa lifutshane: ngeempawu zokubopha kabini, njani ukuzinzisa ngesandi. Le yokugqibela ithintela ukujika simahla xa ujikeleza ibhondi (into exhaphake kolu hlobo lwebhondi), inika i-peptide into engenakuphepheka.

Ngokufanayo, iibhondi zepeptide zinokuthotywa okanye zaphulwe yihydrolysis (ukongezwa kwamanzi), Ukukhulula isixa samandla kwinkqubo ecothayo. Oku kunokukhawuleziswa kubukho be ezikhuthazayo acidic, esisiseko okanye enzymatic.

Imizekelo yeebhondi zepeptidi

Nayiphi na i-peptide ngumzekelo ogqibeleleyo weebhondi ze-peptide, njengoko zisisiphumo solu hlobo lwe-amino acid yokujoyina. Nazi ezinye zezona zibalulekileyo:

1. Bradykinin (Arg-Pro-Pro-Gly-Phe-Ser-Pro-Phe-Arg). Yenziwe ngama-amino acid alithoba, le peptide sisiyobisi esivelisa i-vasodilation kunye nokwehla koxinzelelo lwegazi, yiyo loo nto isetyenziselwa ukunyanga abaguli abanesifo soxinzelelo.
2. I-Oxytocin (Cys-Tyr-Phe-Gln-Asn-Cys-Pro-Arg-Gly-NH)₂). IHormone eveliswe yi-hypothalamus kwaye eyenza imisebenzi ye-neuromodifying yenkqubo ye-nervous system kunye nendima ebalulekileyo kulungiselelo lomlomo wesibeleko sowasetyhini ngexesha lokubeleka kunye nasebeleni ngexesha lokuncancisa.
3. IGlucagon (i-NH2-yakhe-uSer-Gln-Gly-iTr-Thr-Ser-Asp-iTyr-Ser-Lys-iTyr-Leu-uAp-Ser-Arg-Arg-Ala-Gln-Asp-Phe-Val- IGln-Trp-Leu-Met-Asn-Thr-COOH). I-29 ye-amino acid peptide hormone, edityaniswe kwipancreas kwaye yabandakanyeka kwimetabolism yeswekile.
4. Glutathione (γ-glutamyl-L-cysteinylglycine). I-Tripeptide yee-amino acid ezintathu: i-cysteine, i-glutamate kunye ne-glycine, yeyona nto iphambili kwi-antioxidant yeselula, ebakhusela kwii-radicals kunye ne-peroxides yasimahla.
5. IVasopressin (Cys-Tyr-Ile-Gln-Asn-Cys-Pro-Leu-Gly-NH)₂). Ukwahlulahlula i-hypothalamus, ilawula ukubuyiselwa kwakhona kweemolekyuli zamanzi kumchamo, zonyusa uxinzelelo lwazo kwaye zidlala indima ephambili njengomlawuli we-homeostatic yegazi. Yihomoni yesithoba ye-amino acid.
6. I-insulin. Ipolypeptide hormone eyenziwe ngama-amino acid angama-51, afihliweyo yipancreas ukulawula umjikelo weswekile egazini.
7. IProlactin. Ipeptide hormone evuselela imveliso yobisi kumabele oomama. Yenziwe ngokulandelelana kwee-amino acid ezingama-198.
8. ILeptin. Enye i-hormone ye-peptide ecinezela imvakalelo yendlala, kwaye yenziwe ngohlobo lwe-167 yeeamino acid.
9. Ukukhupha. Le peptide hormone ilawula ukuveliswa kweencindi zesisu esiswini. Yenziwe ngama-amino acid ali-14.
10. Pepsin. IHormone yenziwe ngama-amino acid angama-326 amade, anoxanduva lokulawula iinkqubo zokwetyisa kunye nokutya.