Ese gukoresha ogisijeni nyinshi bivuga gukora ATP nyinshi? Amasomo ava mu bushakashatsi ku bururu bwa metilene

Mitochondrion yatandukanyijwe n'akagari iri mu cyumba cy'igerageza kirimo ibiyitanga ingufu ariko nta ADP. Ikoresha ogisijeni buhoro. Iyo hongerwamo ADP, ikoreshwa rya ogisijeni ryiyongera inshuro nyinshi. Iyo utegereje kugeza ADP ishize, ikoreshwa rya ogisijeni rirongera rikagabanuka. Ibiyitanga ingufu ntibyigeze bihinduka. Icyahindutse gusa ni ubukene bwa ATP.

Urwo ruhererekane rugufi rukubiyemo itandukaniro ryose iyi nyandiko isobanura. Ikoreshwa rya ogisijeni ripima umuvuduko elegitoroni zinyuraho mu ruhererekane rw'ihumeka zigana kuri ogisijeni. Ikorwa rya ATP ripima igice cy'urwo rujya n'uruza kibikwamo nk'ingufu zishobora gukoreshwa. Ibyo byombi bifite intambwe bihuriyeho hagati: itandukaniro ry'ubwinshi n'ingufu za porotoni ku mpande z'agahu k'imbere ka mitochondrion. Ikintu cyose gihindura uburyo iryo tandukaniro rihujwe n'ikorwa rya ATP gishobora gutuma ibyo bipimo byombi bihinduka mu byerekezo bitandukanye. Ubururu bwa metilene bufasha kubyumva kuko bwagaragaye bukora ibyo byombi: mu mitegurire imwe y'igerageza, bwongera ikoreshwa rya ogisijeni hamwe na ATP; mu yindi, bwongera ikoreshwa rya ogisijeni mu gihe ATP idahinduka cyangwa igabanuka.

Abasomyi bifuza kubanza kumva ishusho rusange y'uko elegitoroni zihererekanwa bashobora guhera ku buryo ubururu bwa metilene butwara elegitoroni mu ruhererekane rw'ihumeka. Abifuza kumenya amagambo yakoreshejwe mu magerageza ya mbere ya ogisijeni bashobora gusoma icyo ibipimo bya mbere by'ihumeka byagaragaje koko.

Ihumeka, ATP, n'itandukaniro rya porotoni ribihuza

Elegitoroni ziva kuri NADH na FADH2 zinjira mu ruhererekane kuri komplegisi I na II, zikanyura muri komplegisi III zigera kuri sitokorome c, hanyuma zikanyura muri komplegisi IV zigera kuri ogisijeni. Ingufu zirekurwa kuri komplegisi I, III, na IV zisunika porotoni ziva muri matirigisi zijya mu mwanya uri hagati y'uduhu tubiri. Uko gutandukanya umuriro w'amashanyarazi n'ubusharire ni byo bitanga imbaraga zituma porotoni zigenda; igice cyazo kijyanye n'amashanyarazi, ari cyo tandukaniro rya potansiyeli ku mpande z'agahu, ni cyo akenshi kiba kinini kurusha ibindi.

ATP synthase ireka porotoni zigasubira muri matirigisi, igakoresha ingufu zirekuwe mu guhuza ADP na fosifate bikabyara ATP. Bityo urukurikirane ni uru:

ikoreshwa rya ogisijeni, hanyuma gusunika porotoni, hanyuma itandukaniro rya porotoni, hanyuma ikorwa rya ATP.

Ikibazo ni uko porotoni zishobora kugaruka zinyuze mu zindi nzira. Uko kugaruka kose kutanyura muri ATP synthase ni ukumeneka kwa porotoni. Uko kumeneka gutuma uruhurerekane rwongera gusunika za porotoni kugira ngo potansiyeli y'agahu idahinduka, bigakoresha ogisijeni nyinshi nta ATP nyinshi bikora. Iyo kumeneka gukomeye bihagije, ihumeka ritandukana n'ikorwa rya ATP: ikoreshwa rya ogisijeni ririyongera mu gihe ATP idahinduka cyangwa igabanuka, naho ingufu zipfuye ubusa zigasohoka nk'ubushyuhe.

Imimerere ya 3, imimerere ya 4, n'igipimo cyo kugenzura ihumeka

Amagambo asanzwe akoreshwa kuri ibi yakomotse ku bushakashatsi kuri mitochondria zatandukanyijwe n'utugari. Imimerere ya 3 ni ihumeka ribaho hari isubusitara hamwe na ADP: ATP synthase igabanya itandukaniro rya porotoni, potansiyeli y'agahu ikagabanuka, uruhurerekane rukihuta kugira ngo rwongere kuyubaka, kandi ikoreshwa rya ogisijeni rikaba ryinshi kubera ko ATP iba ikorwa. Imimerere ya 4 ni ihumeka ribaho ADP imaze gushira: ATP synthase ntiba igikora, itandukaniro rya porotoni rikiyongera, potansiyeli nini y'agahu ikabangamira gukomeza gusunika porotoni, maze ikoreshwa rya ogisijeni rikagabanuka rikagera gusa ku rikenewe kugira ngo risimbure porotoni zimeneka.

Bityo, igipimo cyo kugenzura ihumeka, kiboneka ugabanyije imimerere ya 3 n'imimerere ya 4, kigaragaza uburyo ihumeka rihujwe neza n'ikorwa rya ATP muri mitochondria ziteguwe gukorwaho igerageza. Igipimo kiri hejuru kivuga ko ADP igenzura ihumeka ku buryo bukomeye. Iyo icyo gipimo kigabanuka mu gihe ihumeka ryo mu mimerere ya 4 ryiyongera, bivuga ko kumeneka kwa porotoni ari byo bigenda byiganza. Ubu ni bwo buryo bwo gusobanukirwa ibisubizo by'ubururu bwa metilene biri hano hepfo.

Hari ishusho imwe yo mu mutwe ikwiye kugumaho. Potansiyeli nini y'agahu ituma uruhurerekane rugenda buhoro. Kuyigabanya bituma rwihuta. Uruhurerekane rusubiza ku ngorane zo gusunika porotoni, ntirusubiza mu buryo butaziguye ku kuba ATP ikorwa cyangwa idakorwa.

Igihe ibipimo byombi bihindukira hamwe

Urugero rusobanutse kurusha izindi rw'ihumeka rihujwe n'ikorwa rya ATP ruva kuri mitochondria zatandukanyijwe n'ubwonko bw'ingurube zo muri Gineya, zifite komplegisi z'ihumeka zahagaritswe. Ku bwinshi bw'ubururu bwa metilene bwa 100 nanomolar kugeza kuri 1 micromolar, ikoreshwa rya ogisijeni mu gihe cyo kuruhuka ryariyongereye hakoreshejwe glutamate hamwe na malate, succinate, cyangwa glycerophosphate nk'ibiyitanga ingufu, ariko ihumeka ryatewe na ADP ntiryahindutse. Muri mitochondria zari zahagaritswe ku rwego rwa komplegisi I cyangwa komplegisi III n'ibintu bizangiza, iryo rangi ryongereye ikorwa rya ATP mu rugero ruto, risubizaho potansiyeli y'agahu, kandi rinonosora kwinjiza kalisiyumu. Inzira yasabwe kubisobanura ni iy'ubusamo: iryo rangi ryakira elegitoroni mbere y'ahafunze rikaziha sitokorome c, bityo rigaca ku ruhande rwa komplegisi yangiritse.

Urugero rwa kabiri rw'ibipimo bihindukira hamwe rukoresha indi soko ya ATP itandukanye rwose. Muri mitochondria zatandukanyijwe n'ubwonko, ATP synthase yazo yahagaritswe, ubururu bwa metilene bwakomeje kongera ihumeka kuri buri subusitara yageragejwe. Ariko ikorwa rya ATP ryiyongereye gusa kuri alpha ketoglutarate na glutamate, ari zo subusitara ebyiri zitanga succinyl CoA. Igihe oligomycin yahagarikaga ATP synthase, ATP yiyongereye yavaga mu kongeraho fosifate ku rwego rw'isubusitara bikorwa na succinyl CoA ligase mu ruhererekane rwa aside sitirike, aho kuva mu kongeraho fosifate gushingiye ku ihumeka. Iryo rangi ryanasubijeho potansiyeli y'agahu igihe komplegisi I na ATP synthase byahagarikwaga icyarimwe. Aha, ikoreshwa rya ogisijeni na ATP byahindukiye hamwe, ariko gusa igihe isubusitara yemereraga iyo nzira ya kabiri yo gukora ATP. Kuri succinate cyangwa malate, ihumeka ryariyongereye nta ATP y'inyongera. Irangi rimwe, icyumba kimwe cy'igerageza, ibitanga ingufu bitandukanye, ibisubizo bitandukanye.

Igihe ibipimo byombi bitandukana

Ingero z'ibipimo bitandukana na zo zaratangajwe kandi zitanga amasomo angana n'ay'izindi. Mu bushakashatsi bwo mu 1997 kuri mitochondria zatandukanyijwe n'umwijima w'imbeba, ubururu bwa metilene bwihutishije ihumeka ryo mu mimerere ya 4 muri mitochondria zakoreshaga succinate kandi ihumeka ryazo ryari rihujwe neza n'ikorwa rya ATP; ibyo byagabanyije igipimo cyo kugenzura ihumeka. Iyo ngaruka yagaragaraga kuva kuri 0.5 micromolar kandi yari ikomeye kuri 5 micromolar, ubwinshi bwegereye ubwagaragara mu gice cy'amazi cy'amaraso nyuma yo gutera mu mutsi 100 milligram icyarimwe. Kuri 5 micromolar, mitochondria zaranabyimbye. Ariko ikibazo cyo guhuza ihumeka n'ikorwa rya ATP cyabanje kugaragara ku bwinshi buri hasi, bikerekana ko kumeneka kwa porotoni kwabanje kwangirika kw'imiterere aho guturuka kuri ko. Muri mitochondria ihumeka ryazo ryari ritandukanye n'ikorwa rya ATP, iryo rangi ryongereye ihumeka mu buryo bwashingiraga ku bwinshi bwaryo kandi bwageraga ku rugero ntarengwa. Ikoreshwa rya ogisijeni ryiyongereye mu mitegurire yombi. Ikorwa rya ATP kuri buri rugero rwa ogisijeni yakoreshejwe ntiryiyongereye. Uru ni urugero rusanzwe rwo gutandukanya ihumeka n'ikorwa rya ATP hamwe no gutwara elegitoroni, byombi bikozwe na molekile imwe.

Itandukana ritangaje kurusha ayandi riva mu gice cy'ijisho cyakira urumuri. Mu mbeba zifite AIF nke no mu tugari twakira urumuri twakoreweho na rotenone, ubururu bwa metilene bwarinze umubyimba w'igice cy'ijisho cyakira urumuri, ibimenyetso by'utugari twakira urumuri, n'imiterere ya mitochondria. Bwanagabanyije igipimo cya NADH ugereranyije na NAD, bugabanya imikorere y'inzira zisubiza ku ihungabana, zirimo igisubizo ku maporoteyine atazinze neza no gusenya mitochondria imbere mu kagari. Bwabikoze butavanyeho ibura rya ATP. Kurinda uturemangingo ingufu zitagaruwe bivuga ko akamaro kanyuze mu kuringaniza ihererekanywa rya elegitoroni no kubungabunga mitochondria, aho kunyura mu gukora ATP y'inyongera. Uwagira ngo kuba uturemangingo twararokotse bivuga ko ubushobozi bwo gukora ingufu bwagaruwe yaba asomye nabi rwose iryo gerageza.

Ubushakashatsi kuri mitochondria zo mu bwonko bwongeraho ikiguzi kuri ibyo byabonetse. Ubwinshi buke bw'ubururu bwa metilene bwanonosoye imikorere y'ingufu muri mitochondria ni na bwo bwongereye ikorwa rya perokiside ya hidirojeni mu mimerere yose yageragejwe kandi bugabanya umuvuduko wo kuyikuraho. Ibyo byapimwe hakoreshejwe ikizamini cya Amplex cyagenzuwe neza, aho gukoresha irangi ritihariye ku kintu gipimwa. ATP nyinshi n'ibintu byinshi byakira elegitoroni byazanye.

Urutonde rw'ibyo kugenzura mu gusoma

Ibibazo bine bitandukanya igisubizo cy'ihumeka rihujwe n'ikorwa rya ATP n'icy'ihumeka ritandukanye na ryo.

Icya mbere, ni ikihe gipimo cyapimwe koko? Ikoreshwa rya ogisijeni ryonyine ntirishobora kugaragaza ATP. Ikorwa rya ATP, potansiyeli y'agahu, n'igipimo cyo kugenzura ihumeka buri kimwe cyongeraho amakuru igikoresho gipima ogisijeni kidashobora kubona. Inyobora yo gusoma ibivugwa mu bushakashatsi ku bururu bwa metilene isobanura birambuye ubu buryo bwo kwitondera ibipimo byafashwe.

Icya kabiri, ni iyihe subusitara yagaburiye mitochondria? Igisubizo cya succinyl CoA cyerekana ko guhitamo ibitanga ingufu bishobora kugena niba ihumeka ry'inyongera rishobora rwose kuvamo ATP y'inyongera.

Icya gatatu, ni ubuhe bwinshi bwakoreshejwe? Ubururu bwa metilene ku bwinshi bwa nanomolar kugeza kuri micromolar nkeya muri mitochondria zo mu bwonko bwatanze inyongera nto mu mikorere y'ingufu, ariko bujyana n'ikiguzi cyo kongera ibintu byakira elegitoroni; kuva kuri kimwe cya kabiri cya micromolar kuzamura, muri mitochondria zo mu mwijima, bwagabanyije ihuzwa ry'ihumeka n'ikorwa rya ATP; kuri 5 micromolar hiyongereyeho kubyimba. Ubwinshi ni igice cy'uburyo ikintu gikora, si amakuru y'inyongera gusa.

Icya kane, ni ubuhe buryo bw'igerageza bwatanze icyo gisubizo? Mitochondria zatandukanyijwe n'utugari zigaragaza imiyoboro y'imikorere, ariko utugari n'uturemangingo bitangiritse byongeraho gutwarwa kw'irangi, guhinduka kwaryo rihabwa elegitoroni rikaba ritagira ibara, n'izindi nzira zihatanira kwakira elegitoroni. Ubushakashatsi bwo muri laboratwari ku ngano zikoreshwa, burimo uburyo ubwinshi n'amabwiriza y'igerageza bigena ingaruka z'ubururu bwa metilene, ni bwo buhuza imibare yo mu cyumba cy'igerageza n'ikivugwa cyose ku muntu.

Ikoreshwa rya ogisijeni rigaragaza urujya n'uruza rwa elegitoroni. ATP igaragaza igice cy'urwo rujya n'uruza cyabitswemo ingufu. Ubururu bwa metilene bushobora guhindura kimwe muri ibyo byombi, kandi amagerageza yavuzwe haruguru yerekana imimerere ine yose ikurikira: byombi biriyongera; ihumeka ririyongera ariko ATP ikiyongera gusa aho isubusitara ibimwemerera; ihumeka ririyongera mu gihe ihuzwa ryaryo n'ikorwa rya ATP rigabanuka; kandi uturemangingo turabungabungwa mu gihe ATP idahinduka. Umubare werekanwa n'igikoresho gipima ogisijeni ni intangiriro yo gusobanura, si iherezo.