Umsebenzi we-Pepsin Enzyme ekugayweni kwamaprotheni
Ukugaya amaprotheni kuyinqubo ebalulekile ohlelweni lokugaya ukudla lomuntu ngoba idlala indima ebalulekile ekwakhekeni nasekulungiseni izicubu, ekwakhekeni kwama-enzyme nama-hormone, nasekulondolozeni isimiso somzimba sokuzivikela. Ukuze umzimba usebenzise amaprotheni okudla, kumele ahlukaniswe abe ama-molecule alula, ikakhulukazi ama-peptide futhi ekugcineni abe ama-amino acid. Le nqubo yokuqhekeka ihilela izitho eziningana kanye nama-enzyme okugaya ukudla, enye yawo yi-pepsin. I-Pepsin yaziwa njenge-enzyme eyinhloko esiswini, eqala ukuqhekeka kwamaprotheni. Lesi sihloko sixoxa ngomsebenzi we-pepsin ekugayweni kwamaprotheni, indlela esebenza ngayo, izimo ezinhle kakhulu, kanye nobudlelwano bayo namanye ama-enzyme okugaya ukudla.
Iyini i-enzyme ye-pepsin?
I-Pepsin iyi-enzyme yokugaya ukudla ekhiqizwa yisisu, ikakhulukazi amaseli ayinhloko odongeni lwesisu. Kodwa-ke, i-pepsin ayikhiqizwa ngokushesha ngesimo sayo esisebenzayo. Isisu sikhiqiza i-pepsin ngesimo esingasebenzi esibizwa ngokuthi i-pepsinogen. Lena yindlela yokuvikela ngoba i-pepsin esebenzayo ingalimaza izicubu zesisu uma ikhishwa ingalawulwa. I-Pepsinogen ibe isisebenza ibe yi-pepsin uma ivezwa endaweni ene-asidi esiswini.
Ukusebenza kwe-Pepsinogen kubangelwa yi-hydrochloric acid (HCl) ekhiqizwa amaseli e-gastric parietal. I-HCl yehlisa i-pH yesisu, idale indawo ene-acid ephezulu, efanelekile ekusebenzeni kwe-pepsin. Ngaphezu kwalokho, amanye ama-pepsin asebenzayo angasiza futhi ekusebenzeni kwamanye ama-pepsinogens ngendlela ye-autocatalytic (ukusebenza kwe-chain).
Indima eyinhloko ye-pepsin: ukuqalisa ukugaya amaprotheni
Umsebenzi oyinhloko we-enzyme i-pepsin ukuphula amaprotheni ayinkimbinkimbi abe yizicucu ezincane, okungukuthi ama-polypeptide nama-peptide. Lesi sigaba sibalulekile ngoba amaprotheni adliwa ekudleni ngokuvamile afika ngesimo sama-molecule amakhulu, agoqiwe (isakhiwo sesithathu). Lawa ma-molecule amakhulu, ayinkimbinkimbi awakwazi ukumuncwa ngqo amathumbu. Ngakho-ke, ukugaya amaprotheni kumele kuqale esiswini ukuze kube lula ukuqhubeka nokucubungula emathunjini amancane.
I-Pepsin isebenza ngokuphula izibopho ze-peptide kumaprotheni, ikakhulukazi lawo ahlanganisa ama-aromatic amino acid njenge-phenylalanine, i-tyrosine, ne-tryptophan. Ngenxa yalokho, iphrotheni ende ekuqaleni ihlukaniswa ibe yizintambo ezimfushane. Nakuba i-pepsin ingakakhiqizi inani elikhulu lama-amino acid amahhala, le enzyme isebenza "njengendlela" yamanye ama-enzyme, okuvumela ukuqhekeka kwephrotheni okuphumelelayo ezigabeni ezilandelayo.
Ubudlelwano phakathi kwe-pepsin ne-asidi yesisu (HCl)
I-Pepsin ayisebenzi yodwa. Ukusebenza kwayo kuncike kakhulu ekubeni khona kwe-HCl. I-asidi yesisu idlala izindima ezintathu ezibalulekile ezihlobene eduze nomsebenzi we-pepsin:
1. Yenza i-pepsinogen isebenze ku-pepsin
Ngaphandle kwezimo ze-asidi, i-pepsinogen ayiguquki ibe yi-pepsin, ngakho-ke ukugaya amaprotheni esiswini akukuhle kangako.
2. Kudala i-pH efanele ukuze i-pepsin isebenze
I-Pepsin isebenza kahle kakhulu ku-pH engaba ngu-1,5–2,5, okuyisimo se-asidi kakhulu. Njengoba i-pH ikhuphuka eduze kwe-neutral, umsebenzi we-pepsin wehla kakhulu.
3. Ukwehlisa izinga lokudla kwamaprotheni
I-asidi yesisu isiza ukuvula isakhiwo seprotheyini (i-denaturation), ukuze kube lula ukuthi izibopho ze-peptide zifinyelele futhi zisikwe yi-pepsin.
Ngakho-ke, i-HCl kanye ne-pepsin ziyizimbangi ezihambisanayo ekuqaliseni ukugaya amaprotheni esiswini.
Isigaba sokusebenza se-pepsin esiswini
Ngemva kokuba ukudla kungene esiswini, inqubo yokuqhekeka kwamaprotheni yenzeka ngezinyathelo eziningana:
1. Ukudla okuxutshwe noketshezi lwesisu
Ukunyakaza kwesisu okuhamba ngaphakathi kwesisu kuphazamisa ukudla nge-HCl nama-enzyme.
2. Amaprotheni ayashintshashintsha
Isakhiwo samaprotheni esiyinkimbinkimbi siqala "ukuvuleka" ngenxa yendawo ene-asidi.
3. I-Pepsin inquma amaketanga amaprotheni
I-Pepsin iphula amaprotheni abe ama-polypeptide amafushane.
4. I-Chyme yakhiwe
Ukudla okuxubile nokugaywa kancane kuba ungqimba olujiyile olubizwa ngokuthi i-chyme, olube selukhishwa kancane kancane emathunjini amancane.
Nakuba ukugaya amaprotheni kuqala esiswini, iningi lenqubo yokuphula amaprotheni abe ama-amino acid yenzeka emathunjini amancane ngosizo lwama-enzyme e-pancreatic nama-enzyme odongeni lwamathumbu.
I-Pepsin iqhathaniswa namanye ama-enzyme okugaya amaprotheni
Ukugaya amaprotheni kuhilela ama-enzyme amaningana anemisebenzi ethile ezindaweni ezahlukene:
– I-Pepsin (isisu): iphula amaprotheni abe ama-peptide amancane endaweni ene-asidi.
– I-Trypsin kanye ne-chymotrypsin (i-pancreas, esebenza emathunjini amancane): iqhubeka nokuqhekeka kwama-polypeptide abe ama-peptide amafushane.
– I-Carboxypeptidase (i-pancreas): inquma ama-amino acid ekugcineni kochungechunge lwe-peptide.
– I-peptidase yamathumbu (umphetho webhulashi): iguqula ama-peptide amancane abe ama-amino acid, ama-dipeptide, noma ama-tripeptide ukuze amuncwe.
Kusukela kulokhu kuqhathanisa, kungabonakala ukuthi i-pepsin idlala indima esigabeni sokuqala futhi iba yisisekelo sesigaba esilandelayo ukuze sihambe kahle.
Izimo ezithinta isenzo se-pepsin
Ngenxa yokuthi i-pepsin incike endaweni yesisu, kunezici eziningana ezingathonya umsebenzi wayo:
1. I-pH yesisu
I-Pepsin iyasebenza ku-pH ene-asidi. Uma i-pH iphezulu kakhulu (ingena-asidi ngokwanele), i-pepsin ingavinjelwa ukusebenza. Isibonelo, ukusetshenziswa isikhathi eside kwemithi yokwehlisa i-asidi kunganciphisa ukusebenza kahle kokugaya amaprotheni kwabanye abantu, yize umzimba ngokuvamile unezindlela zokubuyisela.
2. Impilo yodonga lwesisu
Ukukhiqizwa kwe-Pepsinogen ne-HCl kungancipha uma kunezinkinga zesisu, njenge-gastritis engapheli noma izimo ezithile ezithinta amaseli akhiqiza i-asidi.
3. Inani lamaprotheni ekudleni
Ukuba khona kwamaprotheni kukhuthaza ukukhiqizwa kwe-gastrin, i-hormone ekhulisa ukukhiqizwa kwe-asidi yesisu kanye nama-enzyme okugaya ukudla, ukuze kuthuthukiswe ukugaya kwamaprotheni.
4. Isikhathi sokukhipha isisu
Uma ukudla kuphuma esiswini ngokushesha kakhulu, isikhathi sokusebenza se-pepsin siba sifushane. Ngokuphambene nalokho, ukukhipha kancane esiswini kunikeza i-pepsin isikhathi esengeziwe sokuphula amaprotheni.
Kungani umsebenzi we-pepsin ubalulekile emzimbeni?
Umsebenzi we-pepsin awubalulekile nje kuphela ngoba uphula amaprotheni, kodwa futhi ngoba ukugaya kahle amaprotheni kuhlobene nezidingo ezahlukene zomzimba, njenge:
- Ukutholakala kwama-amino acid okwakha nokulungisa izicubu.
– Ukwakheka kwama-enzyme, ama-hormone kanye nama-antibodies akhiwa kakhulu ngamaprotheni.
– Isekela ukukhula nokululama ngemva kokugula noma ukulimala.
– Isekela imetabolism ngoba amaprotheni angaba umthombo wamandla uma kudingeka.
Uma ukuwohloka kwamaprotheni kuphazamiseka, umzimba ungantula izinto zokusetshenziswa ezibalulekile ngisho noma ukudla amaprotheni kubonakala kwanele.
Isiphetho
I-Pepsin iyi-enzyme eyinhloko esiswini ebangela ukuqala ukugaya amaprotheni. I-Pepsin ikhiqizwa ngendlela engasebenzi (i-pepsinogen) futhi ivuselelwa yi-gastric acid (HCl) ku-pH ene-acid ephezulu. Umsebenzi wayo ukuphula amaprotheni amakhulu abe ama-polypeptide amancane nama-peptide, okuvumela inqubo yokugaya ukudla ukuthi iqhubeke ngempumelelo emathunjini amancane ngama-enzyme e-pancreatic namathumbu. Ngakho-ke, i-pepsin idlala indima ebalulekile ekuqinisekiseni ukuthi amaprotheni okudla acutshungulwa abe yizingxenye ezingamuncwa futhi zisetshenziswe ngumzimba.
Uma uthanda, ngingangeza nomfanekiso wenqubo yokugaya amaprotheni (kusukela emlonyeni-esiswini-emathunjini amancane) noma ngenze inguqulo yesayensi kakhulu yalesi sihloko yemisebenzi yesikole/yasekolishi.
