Potoloho ea Krebs: Potoloho ea Citric Acid ho Metabolism ea Matla
Potoloho ea Krebs, e tsejoang hape e le potoloho ea asiti ea citric, ke letoto la lik'hemik'hale tse bapalang karolo ea bohlokoa metabolism ea sele. E reheletsoe ka Hans Krebs, rasaense oa Jeremane-Brithani ea ileng a e sibolla ka 1937, ke eona e ka sehloohong metabolism ea matla linthong tse phelang tsa aerobic. Sehloohong sena, re tla teba haholoanyane ka mokhoa, karolo le bohlokoa ba potoloho ena baelojing ea sejoale-joale.
Selelekela ho Potoloho ea Krebs
Potoloho ea Krebs e etsahala mitochondria, e leng "matlo a matla" a sele, e leng libaka tsa mantlha tsa tlhahiso ea adenosine triphosphate (ATP), e leng mojari oa matla a sele. ATP e thehoa haholo-holo ka phosphorylation ea oxidative, 'me potoloho ea Krebs e sebetsa e le mohato oa bohlokoa ts'ebetsong ena. Potoloho ena ke karolo ea tsela e kholo ea metabolism e kenyeletsang glycolysis le ketane ea lipalangoang tsa lielektrone.
Pele e kena potolohong ea Krebs, molek'hule ea pyruvic acid, e leng sehlahisoa sa glycolysis, e fetoloa ho ba acetyl coenzyme A (acetyl-CoA). Ts'ebetso ena e lokolla molek'hule e le 'ngoe ea carbon dioxide 'me e hlahisa NADH ho tsoa ho NAD+, e sebelisoang ketane ea lipalangoang tsa lielektrone ho hlahisa ATP.
Mekhahlelo ea Potoloho ea Krebs
Potoloho ea asiti ea citric e na le mehato e robeli ea bohlokoa, e 'ngoe le e 'ngoe e susumetsoa ke enzyme e itseng. Mehato ena ke e latelang:
1. Sebopeho sa Citrate: Acetyl-CoA e kopanya sehlopha sa eona sa acetyl le molek'hule ea oxaloacetate ea khabone tse 'ne, e hlahisang citrate ea khabone tse tšeletseng, ka ketso ea enzyme citrate synthase.
2. Ho Isomerization ea Citrate ho Isocitrate: Ka enzyme aconitase, citrate e feta ho isomerization ho isocitrate ka ho thehoa ha molek'hule ea cisocitrate e mahareng.
3. Ho tlosa oksideishene ea Isocitrate: Isocitrate e oksideishene ke enzyme isocitrate dehydrogenase, e e fetola alpha-ketoglutarate, ha e ntse e lokolla carbon dioxide mme e fetola NAD+ ho NADH.
4. Sebopeho sa Succinyl-CoA: Alpha-ketoglutarate e feta ho decarboxylation ea oxidative ke enzyme alpha-ketoglutarate dehydrogenase, e hlahisang succinyl-CoA le ho lokolla carbon dioxide ea bobeli, hammoho le ho hlahisa NADH.
5. Sebopeho sa Succinate: Ka karabelo e susumetsoang ke succinyl-CoA synthetase, succinyl-CoA e fetoloa ho ba succinate, e boetse e hlahisa molek'hule e le 'ngoe ea guanosine triphosphate (GTP), e ka fetoloang habonolo ho ba ATP.
6. Ho ntsha Succinate ho Fumarate: Enzyme succinate dehydrogenase e susumetsa ho ntsha succinate ho fumarate. Karabelo ena e boetse e hlahisa FADH2 ho tsoa ho FAD, eo hamorao e sebediswang ketane ya dielektrone.
7. Ho Monya ha Fumarate ho Malate: Enzyme fumarase e susumetsa ho eketsoa ha molek'hule ea metsi ho fumarate, e leng se hlahisang malate.
8. Ho ntsha oksideishene ha Malate ho ya ho Oxaloacetate: Mohato wa ho qetela o susumetswa ke malate dehydrogenase, e kgutlisang oksideishene ho malate ho ya ho oxaloacetate, e leng se hlahisang NADH ya ho qetela ho tswa ho NAD+.
Ka ho bopjwa botjha ha oxaloacetate, potoloho e se e loketse ho qala hape ka dimolek'hule tse ntjha tsa acetyl-CoA.
Karolo ea Potoloho ea Krebs Matla a Sele
Ka nako e 'ngoe le e 'ngoe ea potoloho ea Krebs, acetyl-CoA e le 'ngoe e fetoloa ka botlalo, e hlahisa limolek'hule tse peli tsa carbon dioxide, limolek'hule tse tharo tsa NADH, molek'hule e le 'ngoe ea FADH2, le GTP/ATP e le 'ngoe. NADH le FADH2 li fepeloa ka har'a ketane ea lipalangoang tsa lielektrone, moo matla a bolokiloeng a sebelisetsoang ho theha gradient ea proton e matlafatsang tlhahiso ea ATP. Kahoo, leha potoloho ea Krebs e sa hlahise ATP e ngata ka kotloloho, monehelo oa eona o moholo o tlhahisong ea lintho tse fokotsang tse tsamaisang phosphorylation ea oxidative.
Bohlokoa ba Baeloji ba Potoloho ea Krebs
Potoloho ea Krebs ke eona e ka sehloohong sa metabolism ea matla a sele, e nolofalletsang lisele ho sebelisa matla a tsoang mehloling e fapaneng ea limatlafatsi. Li-amino acid, mafura a acid le lik'habohaedreite kaofela li ka aroloa hore e be limolek'hule tse ka kenang potolohong ena. E le ntlha ea bohlokoa ea ho kopana ha metabolism, potoloho ea citric acid e fana ka tsela ea bohlokoa bakeng sa ho hokahana le ho laola litsela tse fapaneng tsa metabolism.
Ho phaella moo, dihlahiswa tse tswang ho potoloho ena di boetse di sebediswa ho etseng di-fatty acid, di-amino acid, le dimolekhule tse ding tsa baeloji, e leng se bontshang ho tenyetseha ha yona le karolo ya bohlokwa ho homeostasis ya sele.
Taolo ea Potoloho ea Krebs
Ts'ebetso ea potoloho ea Krebs e laoloa ke litlhoko tsa matla a sele le ho fumaneha ha substrate. Mekhoa e meng ea taolo e kenyelletsa:
– Thibelo ea Maikutlo: Limolek'hule tse kang ATP, NADH, le lihlahisoa tsa tsona tsa ho qetela li ka thibela ts'ebetso ea li-enzyme potolohong, tsa fokotsa sekhahla sa ts'ebetso ha matla a lekane.
– Li-activator: ADP kapa AMP, tse bontšang litlhoko tsa matla a sele, li ka kenya tšebetsong li-enzyme ho potlakisa potoloho.
– Ho fumaneha ha Substrate: Bongata ba oxaloacetate kapa acetyl-CoA bo ka ama lebelo la potoloho.
Litlamorao tsa Bongaka le Lipatlisiso
Ho se sebetse hantle ha potoloho ea Krebs ho ka kenya letsoho mafung a fapaneng, ho kenyeletsoa kankere, lefu la tsoekere le mathata a methapo ea kutlo. Mohlala, lisele tse ling tsa kankere li bontša liphetoho potolohong ena ho tšehetsa kholo e sa laoleheng, ka hona, likarolo tsa potoloho ea Krebs hangata li reretsoe nts'etsopele ea mekhoa ea phekolo ea kankere.
Lipatlisiso li ntse li tsoela pele ho utloisisa hamolemo taolo ea potoloho ena le kamano ea eona le mafu a batho. Kutloisiso e tebileng e ka lebisa litlhōlisanong tsa ho hlahloba, ho phekola le ho thibela maemo a fapaneng a bophelo bo botle.
Qetello
Potoloho ea Krebs ke eona e ka sehloohong ea metabolism ea matla a sele. E hokahanya le ho nkela mekhoa e meng e mengata ea metabolism sebaka, e tšehetsang tlhahiso ea ATP le biosynthesis ea likarolo tsa bohlokoa tsa sele. Jwalo ka karolo ea bohlokoa ea metabolism, kutloisiso e felletseng ea potoloho ea citric acid e na le litlamorao tse pharaletseng ho tloha saenseng ea motheo ho isa lits'ebetsong tsa bongaka. Ka ho tsoela pele ho batlisisa, potoloho ena e tla lula e le sebaka sa bohlokoa sa thuto ea biochemistry le bongaka.
