Krebs umjikelezo - izigaba eziyinhloko futhi yayithinta eziphilayo

Kwenqwaba amandla carbon chemical ikhishwe ngaphansi kwezimo aerobic ezihilela umoya-mpilo. Umjikelezo Krebs ubizwa nangokuthi umjikelezo citric acid, noma esitokisini kwezimila. Ngo kulungiswa ukusabela ngazinye inqubo yahanjelwa ososayensi abaningi: A. Szent-Gyorgyi, A. Lehninger, X. I Krebs umjikelezo igama inikezwe, SE Severin nabanye.

Phakathi ukuwohloka aerobic kanye anaerobic carbohydrate kukhona ubuhlobo obuseduze correlative roomates. Okokuqala, lubonakaliswa khona pyruvic acid, usuphothuliwe ukugayeka anaerobic carbohydrate futhi iqala kwezimila yeselula (Krebs umjikelezo). Bobabili izigaba kuthiwa catalyzed ngu enzyme efanayo. Amandla amakhemikhali ezikhishwe phosphorylation, kugcinelwe njengoba macroergs ATP. I zamakhemikhali abathintekayo yiwona coenzymes efanayo (nad, NADP) kanye cations. Umehluko zimi kanje: uma anaerobic ukuhlukaniswa carbohydrate ogxile isebenze hyaloplasm, solwazi kwezimila ukusabela zenzeka ikakhulukazi mitochondria.

Ngaphansi kwezimo ezithile, kukhona ukuphikisana phakathi izigaba ezimbili. Ngakho, khona-mpilo yokusabela isilinganiso ka glycolysis incipha ngokucijile (Pasteur umphumela). imikhiqizo glycolysis kungase zivimbela umzimba aerobic carbohydrate (Crabtree umphumela).

Umjikelezo Krebs uchungechunge zamakhemikhali okuholela imikhiqizo nokwehliswa kwesithunzi carbohydrate kuthiwa oxidized ukuba carbon dioxide futhi amanzi, amakhemikhali namandla zanqwabelana compounds amandla-ocebile. Phakathi kwezimila yeselula ikhiqizwa "umthuthi" - oxaloacetic acid (SCHOK). Ngemva kwalokho ukufingqa nge "umthuthi" isebenze ezisalayo acetic acid. Kube tricarboxylic acid - citric. Phakathi zamakhemikhali, kukhona "ithuba" zinsalela e acetic acid umjikelezo. Ngoba i-molecule ngamunye ka pyruvic acid Kumiswa molecule nesishiyagalombili adenozintrifosfatnoy acid. Ekupheleni umjikelezo ikhishwe "umthuthi", okuyinto ihlangana molecule entsha ezisalayo isebenze acetic acid.

Krebs umjikelezo ukuphendula

Uma umkhiqizo ekupheleni ukugaya anaerobic carbohydrate kuyinto acidosis acid, ngaphansi kwethonya dehydrogenase lactate is oxidized ukuba pyruvic acid. Ingxenye molecule pyruvic acid synthesis "umthuthi" SCHOK ukuthonywa pyruvate carboxylase enzyme khona Mg2 + ion. Ingxenye pyruvic acid molecule ungumthombo i "acetate asebenzayo" - atsetilkoenzima A (acetyl-CoA). Ukusabela wenziwa khona ngaphansi kwethonya pyruvate dehydrogenase. Acetyl-CoA iqukethe amandla isibopho, okuyinto aqoqana emhlabeni 5-7% wamandla. Kwenqwaba chemical amandla ezivezwa namachibi of "acetate asebenzayo".

Wathonywa tsitratsintetazy iqala nokusebenza ngendlela efanele Krebs umjikelezo, okuholela kwetinhlavu citrate acid. Le asidi ithonywa akonitat hydratase dehydrogenated iguqulwe ibe le cis-aconitic acid ukuthi ngemva kwalokho-molecule yamanzi ludlulele isocitric. Phakathi acid amathathu tricarboxylic yakhoibrium ashukumisayo Kumiswa.

Isocitric acid is oxidized ukuba oxalosuccinic, okuyinto decarboxylated futhi waguquka waba-alpha-ketoglutaric acid. Ukusabela is catalyzed yi isocitrate enzyme. acid Alpha-ketoglutaric bedle enzyme 2-oxo- (alpha-keto) -glutaratdegidrogenazy decarboxylated, okuphumela ekwakhiweni of succinyl-CoA ehlanganisa amandla isibopho.

In the isinyathelo esilandelayo succinyl-CoA ngu enzyme succinyl-CoA synthetase okuhambisa namandla isibopho GDF (guanozindifosfatnoy acid). GTP (guanozintrifosfatnaya acid) ngaphansi kwethonya adenylate enzyme ithumela GTP-amandla isibopho AMP (adenozinmonofosfatnoy acid). Krebs Cycle: ifomula - GTP + AMP - GDP + Adp.

Succinic acid ngaphansi isenzo enzyme succinate dehydrogenase (LDH) is oxidized ukuze fumaric. SDG coenzyme is flavin adenine ihambisane dinucleotide. Fumarate ukuthonywa fumaratgidratazy enzyme ibizwa ibe malic acid, nakho oxidized ukwakha SCHOK. Ephambi kwezinduna uhlelo ukusabela acetyl-CoA SCHOK futhi kufakwe tricarboxylic acid umjikelezo.

Ngakho, kwakheka umuntu molecule glucose is ukuba 38 molecule ATP (ezimbili - ngenxa glycolysis anaerobic, eziyisithupha - ngenxa namachibi amabili molecule nad · H + H +, okuyinto akhiwa ngesikhathi oksireduktsii glycolytic no-30 - ngenxa TCA). CTLs nekusebenta 0.5. Ezinye izindaba zika-energy kwashabalala njengoba ukushisa. I TCA is oxidized 16-33% lactate acid, lonke isisindo salo sikhulu ku resynthesis ka glycogen.