Uchungechunge zokuphefumula: enzyme obusebenzayo

Zonke ukusabela kwamakhemikhali emangqamuzaneni yimuphi umzimba zenzeka amandla nezindleko. uchungechunge zokuphefumula - ukulandelana izakhiwo ethize zitholakala ulwelwesi engaphakathi mitochondria futhi sikhonze kumiswa ATP. Adenosine liwumthombo enemisebenzi amandla futhi kungaba buthelela lo kJ 80 ukuya kwayi-120.

Zokuphefumula electron uchungechunge - kuyini?

Electron nama-proton zidlala indima ebalulekile emfundweni amandla. Zakha umehluko voltage ezinhlangothini ezilwisanayo ulwelwesi we mitochondria yakha ngokunyakaza iqondiswe izinhlayiya - zamanje. uchungechunge zokuphefumula (ke NJLL, electron ezokuthutha chain) kuyinto umlamuleli lapho kudluliswa izinhlayiya kahle icala esikhaleni intermembrane nezinhlayiyana omubi icala ukushuba ulwelwesi engaphakathi mitochondria.

Iqhaza main kwetinhlavu amandla kungokwalabo ATP-synthase. Lokhu iqoqo eyinkimbinkimbi amandla okushintsha isiqondiso ukunyakaza proton ku kwamakhemikhali amandla izibopho. By the way, icishe lifane nsé eyinkimbinkimbi Itholakala chloroplast izitshalo.

Futhi izakhiwo kwemigudu yokuphefumula uchungechunge enzyme

ukudluliselwa Electron kuhambisana ukusabela kwamakhemikhali khona kohlelo enzyme. Lezi izinto eziphila abakhuthele, amakhophi amaningi akha izakhiwo ezinkulu eziyinkimbinkimbi, ukukhonza abaxhumanisi lapho kudluliswa electron.

Izakhiwo yochungechunge zokuphefumula - yizici lemcoka ezokuthutha izinhlayiya icala. Ubude ku kwangaphakathi ulwelwesi mitochondrial 4 kukhona kumiswa enjalo, kanye ATP synthase. Zonke lezi zakhiwo ukwabelana ukuze kufinyelelwe umgomo ofanayo - Ukugoqa NJLL electron ukudluliswa hydrogen proton esikhaleni intermembrane futhi, ngenxa yalokho, ukuhlanganiswa kwezici ATP.

Isakhiwo yinhlanganisela amaprotheni amangqamuzana, phakathi lapho kukhona ama-enzyme kwesakhiwo namaprotheni okuwuphawu. Ngamunye the izakhiwo 4 yokugcwalisa kuphela yayo wakhe isici, umsebenzi. Ake ubone ukuthi iyiphi imisebenzi ku NJLL ukwethula lezi zakhiwo.

I eziyinkimbinkimbi

Ukudluliswa electron emaqaqasini ulwelwesi mitochondrial indima esemqoka udlalwa yi-chain zokuphefumula. Ukuqedwa ukuphendula hydrogen proton ne-electron lokuhamba nabo - omunye ukusabela main NJLL Isethi yokuqala ezokuthutha uchungechunge eqala molecule nad * H + (e izilwane) noma NADP * H + (izitshalo), kulandele cleavage we-hydrogen-proton ezine. Empeleni, ngenxa yalokhu ukuphendula eziyinkimbinkimbi kwamakhemikhali mina ubizwa nangokuthi NADH - dehydrogenase (okuthiwa emaphakathi enzyme).

Ukwakheka dehydrogenase eziyinkimbinkimbi yensimbi-sulphur amaprotheni zihlanganisa 3 izinhlobo, futhi flavin mononucleotide (FMN).

II eziyinkimbinkimbi

Ukusebenza kwalesi eziyinkimbinkimbi aluhileli ukudluliswa hydrogen proton esikhaleni intermembrane. Umsebenzi oyinhloko le sakhiwo ukuphakela electron ezengeziwe iketango electron ezokuthutha esebenzisa succinate namachibi. Central enzyme eziyinkimbinkimbi - succinate-ubiquinone oxidoreductase, okuyinto catalyzes le cleavage of electron kusukela succinic acid sokudlulisela ubiquinone kuyinto lipophilic.

Umthengisi hydrogen proton ne-electron kuma-complex yesibili futhi mkhuba * H _2. Nokho, i-adenine flavin dinucleotide kahle kunalawo analogue yayo - nad noma NADP * H * H.

Ukwakheka II siqukethe izinhlobo ezintathu eziyinkimbinkimbi yensimbi-sulphur amaprotheni emaphakathi oxidoreductase enzyme succinate.

III eziyinkimbinkimbi

Uphiko olandelayo we-akhawunti, NJLL siqukethe cytochrome b ₅₅₆ b _560, futhi c _1, kanye nensimbi-sulphur amaprotheni Izingozi. Wokuqashwa lesithathu lihlotshaniswa nokudluliswa proton ezimbili ze-hydrogen esikhaleni intermembrane, futhi ama-electron kusukela ubiquinone lipophilic ukuze cytochrome C.

Ubungozi isici amaprotheni wukuthi ancibilikisa emafutheni. Akhona namanye amaprotheni yaleli qembu elalihlanganyela izakhiwo yochungechunge zokuphefumula, ungaphumi lapho ifakwa emanzini. Lesi sici kuthinta isikhundla yezinhlayiya amaprotheni ku ukushuba we kwangaphakathi ulwelwesi mitochondrial.

Isethi wesithathu imisebenzi njengoba ubiquinone-cytochrome c oxidoreductase.

IV eziyinkimbinkimbi

Yena cytochrome-oxidant eziyinkimbinkimbi okungukuthi sasilibangise ku NJLL Umsebenzi waso ukuze uthumele electron kusukela cytochrome c ngoba la ma-athomu umoya-mpilo. Ngemva kwalokho omubi icala O ama-athomu bazothini ne-proton hydrogen ukuze akha amanzi. The main enzyme - cytochrome c oxidoreductase umoya-mpilo.

Isakhiwo eziyinkimbinkimbi wesine kuhlanganisa cytochrome a, _3, futhi ama-athomu zekoporo ezimbili. Iqhaza eliyingqikithi ukudluliselwa electron kuma-mpilo waya cytochrome _3. Ukuxhumana zalezi zakhiwo is bebengaphuzile nitrogen cyanide ne-carbon monoxide, ngomqondo global, kuholela ekunqanyulweni kwe ATP zamagama nasekubhujisweni.

ubiquinone

Ubiquinone - into Vitamin-like, ekhuthaza lipophilic, esishukumisela ngokukhululekile ukushuba we ulwelwesi. mitochondrial uchungechunge sokuphefumula selulwane asikwazi ukukwenza ngaphandle kulesi sakhiwo, isb. k. Kuyinto unesibopho electron ezokuthutha kusukela izakhiwo I neyesi-II kuya kokulukhuni III.

Ubiquinone kuyinto esuselwe benzoquinone. Lesi sakhiwo kungenzeka idluliselwe encwadini kwamaSu Q noma LN esifushanisiwe (ubiquinone lipophilic). I namachibi engqamuzaneni kuholela ekwakhekeni semiquinone - a oxidizer eqinile, okuyinto yingozi cell.

ATP synthase

Iqhaza main kwetinhlavu amandla kungokwalabo ATP-synthase. Lesi sakhiwo isebenzisa gribopodobnaya amandla iqondiswe ezinyakazayo izinhlayiya (proton) ukuze siguqulwa amandla amakhemikhali.

Inqubo eziyisisekelo okwenzeka kulo lonke NJLL - kuyinto namachibi. I chain zokuphefumula unesibopho electron lwezokuthutha ulwelwesi mitochondrial mkhulu futhi inqwaba yabo kuleli matrix. Ngasikhathi sinye, izakhiwo of mina, III no IV akhishwa hydrogen proton esikhaleni intermembrane. icala umehluko ezinhlangothini ulwelwesi kuholela ukunyakaza ohlangothini ka-proton ngokusebenzisa ATP synthase. Njengoba H + ufake matrix, ama-electron zifeziwe (okuhlotshaniswa oksijini) ukwakha into kokungathathi hlangothi ngokuba iseli - amanzi.

ATP synthase f0 siqukethe futhi F1 subunits okuyinto ndawonye bakha i-molecule ye-router. F1 lakhiwe ngemalunga lamatsatfu ezintathu alpha ne-beta subunits, okuyinto ndawonye bakha siteshi. Lesi siteshi ncamashi ububanzi efanayo, okuyinto abe proton hydrogen. Nge ukudlula izinhlayiya kahle icala ngokusebenzisa ATP synthase ikhanda molecule F ₀ osontekile by 360 emhlabeni-axis awo. Phakathi nalesi sikhathi, ukuba AMP noma Adp (adenozinmono- futhi diphosphate) inamathelisiwe phosphate ezisalayo nge izibopho ephezulu amandla, okuyinto azungeze semali amandla.

ATP synthase atholakala emzimbeni, hhayi kuphela e-mitochondria. Ngo izitshalo, lezi izakhiwo nazo esisogwini ulwelwesi we vacuoles (tonoplast), kanye thylakoids chloroplast.

Futhi e isilwane amaseli bese isitshalo ATPases abakhona. Sinenkosi isakhiwo efanayo ukuthi we ATP synthase, kodwa kungani leso senzo sabo iqondiswa ku nokuqedwa kwe-phosphate izinsalela ukuba bachitha amandla.

Okwakushiwo begazi iketango zokuphefumula

Okokuqala, ukuphela umkhiqizo NJLL ukusabela yiyona okuthiwa amanzi umzimba (300-400 ml ngosuku). Okwesibili, ukuhlanganiswa kwezici ATP kanye ne-energy storage yizibopho kwamakhemikhali engqamuzaneni. Ngezinye usuku 40-60 kg adenosine is kuhlelwe umqondo, futhi okufanayo isetshenziswa enzymatic ukusabela amaseli. Ukuphila komunye molecule ATP iminithi elingu-1, ngakho iketango zokuphefumula kumele zihambe ngokushelela ngokunembile futhi ngaphandle amaphutha. Kungenjalo, iseli uzofa.

Mitochondria ezibhekwa iziteshi amandla noma iyiphi iseli. Inombolo yabo incike amandla adingekayo kwimisebenzi ethile. Ngokwesibonelo, izinzwa bungabalwa abafika kwabangu-1000 mitochondria okuvame akha cluster ku zokuxhumana zobuchopho okuthiwa uqweqwe.

Umehluko phakathi iketango zokuphefumula ezitshalweni nasezilwaneni

Ngo izitshalo, i olwengeziwe "izitshalo amandla" esitokisini kuyinto chloroplast. On ulwelwesi kwangaphakathi yalezi organelles ayatholakala ATP synthase, futhi lokhu kuyinto inzuzo phezu amaseli isilwane.

Futhi izitshalo angaphila e lokuhlala eliphezulu carbon monoxide, i-nitrogen ne-cyanide ngenxa indlela cyanide ukumelana kule NJLL ngaleyo ndlela uchungechunge zokuphefumula luphele ubiquinone, okuyindawo electron ngokuqondile idluliselwe athomu umoya-mpilo. Ngenxa yalokho, kancane ATP is kuhlelwe, Nokho, lesi sitshalo angaphila kwezimo ezingezinhle. Izilwane ezimweni ezinjalo, ukuvezwa kwesikhathi eside ukuba afe.

Singafanisa nekusebenta nad, mkhuba futhi indlela cyanide nemithi ngokusebenzisa ATP inkomba kumiswa uma udlulisa 1 electron.

• nge nad noma NADP ezakhiwe 3 molecule ATP;
• kwakhiwa mkhuba ubizwa amabili molecule ATP;
• ka-cyanide yakha 1 esimeme endleleni ATP-molecule.

ukubaluleka kwemvelo of NJLL

Ngoba zonke izinto eziphilayo eukaryotic, umthombo enkulu amandla iketango zokuphefumula. Biochemistry ATP zamagama kuseli ihlukaniswe izinhlobo ezimbili, substrate phosphorylation futhi oxidative phosphorylation. NJLL isetshenziswa synthesis uhlobo lwesibili yamandla, isb. E. Ngenxa redox ukusabela.

Ezintweni eziningi eziphilayo prokaryotic ATP kwakhiwa kuphela substrate phosphorylation e glycolysis esiteji. Six-carbon ushukela (mhlawumbe glucose) Kuhlanganisani umjikelezo ukuphendula, futhi ingqamuzana okukhipha uthola ezimbili molecule ATP. Lolu hlobo amandla ubhekwa synthesis bakudala kakhulu, isb. K. Eukaryotes ngesikhathi phosphorylation oxidative kwakhiwa 36 ATP molecule.

Nokho, lokhu akusho ukuthi izitshalo lanamuhla nezilwane abalahlekelwe ikhono substrate phosphorylation. Vele lolu hlobo ATP zamagama wayewukuphela kwesisebenzi kweengaba ezintathu energy production kuseli.

Glycolysis e eukaryotes senzeka cytoplasm esitokisini. Kukhona zonke enzyme kudingekile ezingaba ninamathele glucose ezimbili molecule pyruvic acid ukwakha 2 molecule ATP. Zonke izinyathelo okwalandela kwenzeke matrix mitochondrial. Krebs umjikelezo noma tricarboxylic acid umjikelezo, njengoba kwenzeka esikhathini mitochondria. Lokhu ivaliwe uchungechunge ukusabela ngenxa okuyinto synthesize nad futhi mkhuba * H * H2. Lezi zinhlayiya izosetshenziswa njengoba consumable e NJLL