Ukuhlanganiswa kwe-cholesterol kungenye yezinqubo ezibaluleke kakhulu ze-metabolic emzimbeni womuntu.
I-biosynthesis ye-cholesterol yenziwa ngamaseli wesibindi - ukukhiqizwa kwaleli khemikhali kungenye yemisebenzi ebaluleke kakhulu eyenziwa yisibindi.Ukuhlanganiswa kwamahomoni e-steroid, uvithamini D, nezakhi ezihambisa ezinye izinto kuncike kwinqubo ye-biochemical ye-cholesterol synthesis.
Ngabe kwenzeka kanjani inqubo yokuphilayo ye-cholesterol synthesis emzimbeni futhi kwenzeka kanjani uma kwenzeka kwephulwa izinqubo zemvelo zokuqanjwa kwale khompiyutha?
Izigaba zenqubo ye-cholesterol biosynthesis emzimbeni womuntu
Inani elikhulu lokudla okudliwe ngabantu liqukethe i-cholesterol. Imikhiqizo enjalo ikhona cishe ekudleni komuntu kwansuku zonke.
I-cholesterol ekwakhiweni kwemikhiqizo ngenxa yokubola ine-density ephansi futhi ibizwa ngokuthi i-cholesterol embi. Umzimba awukwazi ukusebenzisa lolu hlobo lwamakhompiyutha ngokuphendula kokuqamba. I-cholesterol embi iyatholakala emzimbeni njengama-lipoprotein aphansi.
Ngokweqile kwabo, le ngxenye yama-plasma precipitates, enza ama-cholesterol plaque ezindongeni zemithambo yegazi, okuholela ekwakhiweni kwe-atherossteosis.
Isibindi sinomsebenzi wokuhlanganisa i-cholesterol enhle, emelelwa ngabantu abaphezulu kakhulu be-lipoprotein. Ngasikhathi sinye, amangqamuzana wesibindi ahlunga i-LDL futhi kancane kancane asuse le ngxenye emzimbeni ngesimo se-bile. Lo msebenzi wesibindi uvimbela ukuqhubekela phambili okusheshayo kwezinguquko ze-atherosulinotic.
Ukwakheka kwamangqamuzana e-cholesterol esibindini kwenziwa ngamaseli athile wezicubu zesibindi - i-hepatocytes.
Isici salawa maseli ubukhona be-reticulum eyenziwe kahle eyenziwe yaqina. Le organelle cellular ibhekele ukwenziwa kwamakhompiyutha okulesigaba sama-carbohydrate namafutha.
Ukuqanjwa kwe-LDL kwenziwa ngezigaba.
Kafushane nje, uhlelo lwe-LDL biosynthesis lungachazwa kulezi zinyathelo ezilandelayo:
- ukukhiqizwa kwe-mevalonate;
- synthesis of isopentenyl pyrophosphate;
- ukwakheka kwe-squalene;
- i-lanosterol synthesis;
- synthesis cholesterol.
Sekukonke, ohlelweni lwe-cholesterol biosynthesis, kunokuphambana okungamakhemikhali okungama-30. Konke lokhu kuhlangana kuhlukaniswe ngezigaba.
Ikhompiyutha yokugcina esibindini somuntu ihlanganiswa ngesilinganiso se-0.5-0.8 g / ngosuku. Kuleli nani, cishe i-50% yesakhiwo yakhiwa esibindini futhi icishe ibe ngu-15% emathunjini.
I-enzyme eyinhloko yokwakheka kwe-cholesterol yi-hydroxymethylglutaryl-SKoA-reductase, umsebenzi we-enzyme ungashintsha izikhathi eziyi-100 noma ngaphezulu.
Ukuhlukahluka okunjalo okuphezulu komsebenzi kuvumela ukugcina okuqukethwe kwe-cholesterol kumthamo we-intracellular ngokwezinga eliqhubekayo.
Ukuhlaziywa kwesilinganiso se-biosynthesis kukhombisa ukuthi ingavinjelwa yiprotheni ethwele ethize, enikezela ukuthuthwa kwezakhi zomzimba eziphakathi nendawo ezenziwe ngesikhathi sokuhlanganiswa kwe-cholesterol.
Ukuphela kwendlela yokususa le nto emzimbeni yi-bile.
Ukusabela kwe-cholesterol biosynthesis
Ukuqanjwa kwe-cholesterol kuqala ngokwakhiwa kwe-mevalonate, ngenxa yalesi sizathu inani elikhulu le-glucose, eliqukethwe inani elikhulu ekudleni okumnandi nasezinsinini.
Ushukela ngaphansi kwethonya lama-enzyme athile uhlukaniswe ngamangqamuzana amabili e-acetyl-CoA. I-Acetoacetyltransferase, i-enzyme eguqula i-acetyl-CoA ibe yi-acetyl-CoA, ihlangana nekhompiyutha eyumphumela. I-Mevalonate yakhiwa kusukela kwinto yokugcina ngokusetshenziswa ngokulandelana kokuphendula okuningi kwamakhemikhali.
Lapho ukhiqiza inani elanele le-mevalonate. ukugcwala kwayo ku-retopulum ye-endoplasmic yeseli yamaseli wesibindi, isigaba esilandelayo sokuhlanganiswa, siqala ukukhiqizwa kwe-isopentenyl pyrophosphate.
Kulesi sigaba, kwenziwa i-phosphorylation yama-mevalonate. I-phosphate yale njongo inika i-ATP, okuwumthombo wamandla wendawo yonke yeseli.
Isinyathelo esilandelayo ukuvela kwe-squalene kusuka ku-isopentenyl pyrophosphate. Lesi sigaba senziwa ngenxa yochungechunge lokuvuselelwa okulandelanayo, ngenxa yalokho okukhishwa amanzi.
Esigabeni sokwakhiwa kwe-isopentenyl pyrophosphate, i-ATP isetshenziswa njengomthombo wamandla esitokisini, futhi esigabeni sokwakhiwa kwe-squalene, izinhlaka zamaselula zisetshenziswa njengomthombo ohlinzeka ngayo yonke inqubo ngamandla we-NADH.
Isigaba se-penultimate of the changes changes in cholesterol synthesis ukwakheka kwe-lanosterol. Le nqubo ifaka phakathi ukususwa kwamanzi. Umphumela woshintsho ukuguqulwa kwe-molecule ye-lanosterol kusuka ekunwetshisweni kuye kwi-cyclic. Kulesi sigaba, i-NADPH isebenza njengomthombo wamandla.
Ukuguqulwa kwesimo se-cyclic se-lanosterol ku-cholesterol kwenzeka ezingxenyeni ze-membrane ze-endoplasmic reticulum ze-hepatocytes.
I-molecule ye-lanosterol ishintsha ibe isibopho esiphindwe kabili kwikhethini yekhabhoni. Le nkimbinkimbi yokuguqulwa kwamakhemikhali idinga inani elikhulu lamandla. Ukunikezwa kwamandla kwalesi sigaba se-biosynthesis kunikezwa ngama-molecule e-NADPH.
Ukusuka ku-lanossterol eshintshiwe, ngokuchayeka kuma-enzymes e-transformer ahlukile, kwakheka i-cholesterol.
Zonke izigaba zokuhlanganiswa zilawulwa yizinhlobonhlobo zama-enzyme nabanikeli bamandla.
Isibonelo somphumela onjalo umphumela we-biosynthesis yama-hormone e-thyroid kanye ne-insulin.
Ukushoda kanye ne-cholesterol eyeqile emzimbeni
Ukuntuleka kwe-cholesterol emzimbeni kungenzeka ngenxa yokuqhamuka kwezifo ezithile emzimbeni.
Ngokuntuleka kwe-cholesterol, umuntu uba nezinkinga ezihambisana nokuntuleka kokukhiqizwa kwama-hormone ocansi ne-Vitamin D.
Ngaphezu kwalokho, ukushesha kwezinqubo zokuguga nokufa kweseli ngenxa yokubhujiswa kwezakhiwo ze-membrane kuyabonakala. Kukhona futhi ukwehla kokungazinzi komzimba kanye nokwehla kwesisindo somzimba ngenxa yokuqhekeka okunganele kwamafutha.
Izifo lapho kunokwanda kwe-cholesterol yilezi:
- Thayipha isifo sikashukela sesi-2.
- I-Pathology ku-gland yegilo.
- Ukwehluleka kwenhliziyo.
- I-genetic pathologies, ukuthuthukiswa kwayo okusiza ukunciphisa i-cholesterol ku-plasma yegazi.
Inkinga ye-cholesterol ephansi ixazululwa ngokubheka izindlela ezikhethekile zokudla ezingakhulisa i-cholesterol yegazi.
Imvamisa, kuvama izimo lapho kuba nokwanda kwe-cholesterol bese kuthi ukuvela ngokweqile kwale ngxenye emzimbeni.
Izizathu zalokhu kwephula umthetho zingaba:
- i-hepatitis kanye ne-cirrhosis;
- ukuba khona kwesisindo somzimba ngokweqile;
- ukwephulwa kwe-cholesterol metabolism;
- izinqubo zokuvuvukala ezikhula emzimbeni.
Ukwehlisa i-cholesterol emzimbeni, kusetshenziswa izidakamizwa ezikhethekile, isenzo sale mishanguzo kuhloswe ngaso ukukhipha i-cholesterol emzimbeni.
I-cholesterol ethe xaxa iholela ekwakhiweni kwama-cholesterol amana nokukhula kwe-atherosulinosis, okungaholela ekushayweni noma ekushayweni yinhliziyo.
Yonke imininingwane eyisisekelo mayelana ne-cholesterol inikezwe kuvidiyo kule ndatshana.
