Yana da matukar muhimmanci a fahimci yadda ake kira cholesterol a hanta ke faruwa. Idan kayi nazarin wannan batun daki-daki, nan da nan zai fito fili yasan menene alakar hanta da wannan kwayar halitta. Amma da farko kuna buƙatar tunawa cewa abu shima yana da suna, wanda kuma galibi ana amfani dashi, shine cholesterol.
Kamar yadda muka riga muka fada a sama, wannan sinadari kwayar halitta ce kuma ana samun ta cikin dukkanin halittu masu rai. Babban bangare ne na abubuwan sha.
Ana lura da mafi girman hankali a samfuran asalin dabbobi. Amma a samfuran tsire-tsire akwai ƙaramin ɓangaren wannan fili.
Hakanan yana da mahimmanci a lura da gaskiyar cewa tare da abinci kawai kashi 20% na adadin adadin cholesterol ya shiga, sauran kashi 80 ɗin jiki yana samarwa da kansa. Af, daga cikin dukkanin abubuwan da aka kera su kadai, kashi 50% ana yin su ne kai tsaye a cikin hanta. Wannan yana faruwa a matakin salula, sauran kashi 30% ana samarwa a cikin hanji da fata.
Jikin ɗan adam ya ƙunshi nau'ikan wannan nau'in. A lokaci guda, ya kamata a lura cewa tsarin hematopoietic ne wanda aka ciko da wannan kayan. Cholesterol a cikin jini wani bangare ne na hadaddun mahadi tare da furotin, ana kiransu abubuwan da ake kira lipoproteins.
Hadaddun na iya zama nau'ikan biyu:
- HDL - suna da yawa sosai, ana kiran su da kyau;
- LDL - suna da ƙarancin yawa, waɗannan abubuwan ana kiransu mara kyau.
Nau'i na biyu ne da ke kawo hatsari ga mutane. Bayan an sanya su, wanda ya ƙunshi lu'ulu'u ne na abu, sai su fara tara abubuwa ta hanyar filaye a jikin bangon jijiyoyin jini, da alhakin jigilar jini. Sakamakon haka, wannan tsari ya zama sanadin ci gaba a cikin jikin wannan cuta kamar yadda atherosclerosis.
Ci gaban atherosclerosis yana haifar da ci gaba da cututtuka masu yawa.
Abubuwan haɗin haɗin asali
Kamar yadda aka ambata a sama, wannan kayan zai iya zama da amfani ga mutane, ba shakka, kawai idan muna magana ne akan HDL.
Dangane da wannan, ya zama a sarari cewa ikirarin cewa cholesterol yana da lahani ga ɗan Adam kuskure ne.
Cholesterol kasancewarsa kwayar halittar halitta:
- ya shiga cikin tsarin halittar jima'i;
- yana tabbatar da aiki na al'ada na masu karɓar serotonin a cikin kwakwalwa;
- shine babban bangaren bile, haka kuma sinadarin bitamin D, wanda yake daukar nauyin shan mai;
- yana hana aiwatar da lalata rukunin abubuwan kwatankwacin ƙwayar cuta a ƙarƙashin tasirin tsattsauran ra'ayi.
Amma tare da kyawawan kaddarorin, kayan suna iya samun lahani ga lafiyar ɗan adam. Misali, LDL na iya haifar da ci gaban cututtuka masu mahimmanci, da farko suna ba da gudummawa ga ci gaban atherosclerosis.
A cikin hanta, an samar da kwayoyin halitta a ƙarƙashin rinjayar HMG redutase. Wannan shine babban enzyme wanda aka haɗo da shi daga biosynthesis. Inhibation na kira na faruwa a ƙarƙashin rinjayar mummunan ra'ayi.
Tsarin kirkiro wani abu a cikin hanta yana da wata alaƙar dangantaka tare da yawan sinadarin da yake shiga jikin mutum da abinci.
Ko da mafi sauki, an bayyana wannan tsari ta wannan hanyar. Hannun kansa yana daidaita matakan cholesterol. Duk lokacin da mutum ya ci abinci mai dauke da wannan kayan, to sai an samar da karancin abu a jikin kwayoyin halittar, kuma idan muka yi la’akari da cewa ana cin kitsen tare da kayayyakin da ke dauke da shi, to wannan tsari na tsari yana da matukar muhimmanci.
Fasali na aikin kwayoyin halitta
Tsofaffi masu lafiya na yau da kullun suna haɓaka HDL a cikin kimanin kimanin 1 g / rana kuma suna cinye kusan 0.3 g / rana.
Matsayi na yau da kullun na cholesterol a cikin jini yana da irin wannan darajar - 150-200 mg / dl. Kula da galibi ta hanyar sarrafa matakin kira na denovo.
Yana da mahimmanci a san cewa hadaddiyar HDL da LDL na asalin halittar an rage ta hanyar rage cin abinci.
Ana amfani da sinadarin cholesterol, daga abinci da kuma hadadden hanta, a cikin samuwar membranes, a cikin kwayar halittun steroid da kuma bile acid. Ana amfani da mafi girman kashin a cikin abubuwan da ake kira bile acid.
An ci gaba da ɗaukar abubuwan HDL da LDL ta sel kwatankwacin matakan abubuwa uku:
- Gua'idar Aiki na HMGR
- Rea'idar ƙwayar cholesterol da ta wuce kima ta hanyar aikin O-acyltransferase sterol, SOAT1 da SOAT2 tare da SOAT2, wanda shine babban aiki mai yawa a cikin hanta. Tsarin farko na waɗannan enzymes shine ACAT don acyl-CoA: cholesterol acyltransferase. Enzymes ACAT, ACAT1, da ACAT2 sune acetyltransAra acetyltransferases 1 da 2.
- Ta hanyar sarrafa matakan cholesterol na plasma ta hanyar LDL-mai karɓar karɓaɓɓen karɓa da HDL-matsakaita jigilar kayayyaki.
Rea'idar aikin HMGR shine ainihin hanyar sarrafa matakin biosynthesis na LDL da HDL.
Enzyme ana sarrafawa ta hanyoyi daban-daban guda huɗu:
- hana hana ruwa gudu;
- kula da bayyana asalin;
- raunin enzyme;
- murza-mai murdiya.
Hanyoyin sarrafa abubuwa uku na farko suna aiki kai tsaye akan abu da kansa. Cholesterol yana aiki azaman mai mayar da martani tare da HMGR da ke gabanta kuma yana haifar da lalata lalacewar enzyme. Latterarshen sakamakon sakamakon polyubiquitilation na HMGR da lalata shi a cikin kariya. Wannan ikon shine sakamakon yanki mai kula da sinadarai na HMGR SSD.
Bugu da ƙari, lokacin da ƙwayar ƙwayar ƙwayar cuta ta kasance fiye da kima, yawan adadin mRNA don HMGR yana raguwa a sakamakon raguwar bayyanar asalin.
Enzymes da ke cikin aikin
Idan kayan aikin exogenous an tsara su ta hanyar canjin gyare-gyare na covalent, za'a aiwatar da wannan hanyar sakamakon phosphorylation da dephosphorylation.
Enzyme yana aiki sosai a cikin tsari mara tsari. Phosphorylation na enzyme yana rage aikinsa.
HMGR ana amfani dashi ta hanyar samar da furotin na AMP-mai aiki, AMPK. AMPK kanta tana kunnawa ta hanyar phosphorylation.
Enzymes akalla biyu ana ɗaukar ƙarfin murfin AMPK, sune:
- Babban kinase da ke da alhakin kunnawa AMPK shine LKB1 (hanta kinase B1). An gano LKB1 da farko a matsayin kwayar halitta a cikin mutane wanda ke ɗauke da maye gurbin maye gurbinsa a cikin ƙwaƙwalwar Putz-Jegers, PJS. Hakanan LKB1 an gano cewa yana cikin maye a adenocarcinoma.
- Na biyu phosphorylating enzyme AMPK shine sinadarin-nutsuwa mai dogaro mai gina jiki kinase kinase kinase (CaMKKβ). CaMKKβ yana haifar da phosphorylation na AMPK a cikin karuwa don karuwa a cikin Ca2 + cikin ƙwayar jijiyoyin ƙwaƙwalwa sakamakon lalacewar tsoka.
Gua'idar HMGR ta hanyar sauye sauye yana ba da damar samar da HDL. HMGR ya fi aiki a cikin yanayin ɓarna. Phosphorylation (Ser872) yana dauke da enzyme na protein na AMP-AMPK, ayyukan wanda shima yake amfani da shi ta hanyar phosphorylation.
Phosphorylation na AMPK na iya faruwa saboda aƙalla enzymes biyu:
- LKB1;
- CaMKKβ.
Howaƙwalwar ƙwayar HMGR, dawo da ita zuwa yanayin aiki mai ƙarfi, ana aiwatar da ita ta hanyar ayyukan phosphatases na furotin na 2A. Wannan jerin yana ba ku damar sarrafa ayyukan HDL.
Me ke shafar nau'in cholesterol?
PP2A aikin yana kasancewa ne a cikin nau'ikan katako iri daban-daban guda biyu wadanda aka sanya su ta hanyar PPP2CA da PPP2CB. Manyan hanyoyin biyu na PP2A sune enzyme heterodimeric da heterotrimeric holoenzyme.
Babban enzyme PP2A ya ƙunshi substrate na scaffold (wanda ake kira da farko A subunit) da kuma subunit catalytic (C subunit). Abun kula da cataltic α ana amfani da shi ta hanyar PPP2CA, kuma ana amfani da sashin kulawar catolitic by PPP2CB.
Sigar halittar f scaffold an sanya ta ta hanyar PPP2R1A gene da kuma un subunit ta hanyar PPP2R1B. Babban enzyme, PP2A, yana hulɗa tare da m subinit subinit don tara cikin holoenzyme.
Subarancin sarrafa PP2A sun haɗa da iyalai huɗu (waɗanda ake kira asali-B subunits), kowannensu ya ƙunshi abubuwa da yawa da aka haɗa ta hanyar kwayoyin halitta daban-daban.
A halin yanzu, akwai nau'ikan halittu iri daban-daban guda 15 don gudanar da aikin na PP2A B. Babban aikin ayyukan rakodin na PP2A shine a ƙaddara abubuwan kariya na phosphorylated substrate zuwa aikin phosphatase na sashin katako na PP2A.
PPP2R yana daga cikin ƙananan matakan 15 na tsarin PP2A. Hormones kamar glucagon da adrenaline suna cutar cholesterol biosynthesis ta haɓaka ayyukan takamaiman ƙayyadaddun kayan aiki na enzymes iyali na PP2A.
PKA-matsakaici phosphorylation na sashin kulawa na PP2A (PPP2R) yana haifar da sakin PP2A daga HMGR, yana hana dephosphorylation. Ta hanyar magance tasirin glucagon da adrenaline, insulin yana ƙarfafa cirewar phosphates kuma hakan yana ƙara ayyukan HMGR.
Reguarin ƙa'idar HMGR yana faruwa ta hanyar hanawa da martani tare da ƙwaƙwalwar ƙwayar cuta, kazalika da ka'idodin ƙirar sa ta haɓaka matakin ƙwayar kwayar intracellular da sterol.
Wannan sabon abu na ƙarshen yana da alaƙa da sashin fassarar SREBP.
Yaya tsari a cikin jikin mutum?
Hakanan ana kulawa da ayyukan HMGR ta hanyar sa hannu tare da AMP. Increaseara yawan cAMP yana haifar da kunnawa ga ƙwayar cAMP-dependant kinase, PKA. A cikin yanayin tsarin HMGR, PKA phosphorylates sashin sarrafawa, wanda ke haifar da karuwar sakin PP2A daga HMGR. Wannan yana hana PP2A cire phosphates daga HMGR, yana hana sake farfadowa.
Babban iyali na tushen furotin phosphatase subunits suna tsarawa da / ko hana ayyukan yawancin phosphatases, gami da membobin PP1, PP2A, da PP2C iyalai. Baya ga PP2A phosphatases wanda ke cire phosphates daga AMPK da HMGR, phosphatases na protein phosphatase 2C (PP2C) suma suna cire phosphates daga AMPK.
Lokacin da waɗannan tsarin mulki suka samar da phosphorylate PKA, ayyukan ɗaure phosphatases yana raguwa, yana haifar da AMPK ya ragu a cikin phosphorylated da aiki mai aiki, da HMGR a cikin phosphorylated da m aiki. Yayinda aka cire mai motsawa, yana haifar da karuwa a cikin samar da cAMP, matakin phosphorylation yana raguwa, matakin dephosphorylation yana ƙaruwa. Sakamakon ƙarshen shine dawowa zuwa matakin mafi girma na ayyukan HMGR. A gefe guda, insulin yana haifar da raguwa a cikin cAMP, wanda, bi da bi, yana kunna ƙirar. Sakamakon ƙarshen shine dawowa zuwa matakin mafi girma na ayyukan HMGR.
A gefe guda, insulin yana haifar da raguwa a cikin cAMP, wanda, bi da bi, yana kunna haɗin cholesterol. Sakamakon ƙarshen shine dawowa zuwa matakin mafi girma na ayyukan HMGR. Insulin yana haifar da raguwa a cikin cAMP, wanda, bi da bi, ana iya amfani dashi don haɓaka tsarin aikin.
Arfin ta da insulin da hana glucagon, ayyukan HMGR ya yi daidai da tasirin waɗannan kwayoyin halittar a kan sauran hanyoyin rayuwa. Babban aikin wadannan kwayoyin halittar guda biyu shine sarrafa damar shigo da kuzari ga dukkan kwayoyin jikinsu.
Tsawon lokaci na ayyukan HMGR ana aiwatar dashi galibi ta hanyar sarrafa kwayar halitta da lalacewar enzyme. Lokacin da matakan cholesterol suka yi yawa, matakin martanin HMGR yana bayyana raguwa, kuma a gefe guda, ƙananan matakan suna kunna maganar asalin.
Ana ba da bayani game da cholesterol a cikin bidiyon a cikin wannan labarin.
