Gcwalisa i-oxidation ye-glucose. Ukuphendula kwe-oxidization ye-glucose

Kule nqaku, siza kujonga indlela i-oxidation ye-glucose eyenzeka ngayo. I-carbohydrate yimizimba ye-polyhydroxycarbonyl uhlobo, kunye neziphumo zazo. Imiqondiso yempawu - ubukho bamaqela e-aldehyde okanye e-ketone kwaye ubuncinane amaqela amabini e-hydroxyl.

Ngokwakhe isakhelo se-carbohydrate zihlukaniswe zibe yi-monosaccharides, i-polysaccharides, i-oligosaccharides.

Monosaccharides

I-Monosaccharides yiyona i-carbohydrate elula engenakukwazi ukuyi-hydrolyzed. Kuxhomekeke kwiqela elikhoyo kwi-composition-aldehyde okanye ketone, ihlukanisa i-aldoses (ezi ziquka i-galactose, i-glucose, i-ribose) kunye ne-ketoses (ribulose, fructose).

IOligosaccharides

I-Oligosaccharides i-carbohydrate enesibini ukusuka kwii-2 ukuya kwi-10 ezihlala kwi-monosaccharide ezixhunyiwe zizibophelelo ze-glycosidic. Ngokuxhomekeke kwisixa semali esele i-monosaccharide, ama-disaccharides, i-trisaccharides njalonjalo. Kwenzeka ntoni xa i-glucose idibene? Oku kuya kuxutyushwa kamva.

Polysaccharides

I-Polysaccharides i-carbohydrate equlethe i-monosaccharide i-resios i-resix ezilishumi ezihlanganiswe kunye nezibopho ze-glycosidic. Ukuba i-polysaccharide efanayo iqulethe i-monosaccharide efanayo, ibizwa ngokuba yi-homopolysaccharide (umzekelo, isitashi). Ukuba ezo zintsalela zihlukile - ke i-heteropolysaccharide (umzekelo, i-heparin).

Yintoni ebalulekileyo ye-oxidation ye-glucose?

Imisebenzi ye-carbohydrate emzimbeni womntu

I-carbohydrates yenza imisebenzi elandelayo:

1. Amandla. Umsebenzi obaluleke kakhulu we-carbohydrates, njengoko ikhonza njengomthombo oyintloko wamandla emzimbeni. Ngenxa yesiphumo sabo, i-half-power of human needs needs. Njengomphumo we-oxidation yegramu enye ye-carbohydrates, i-16.9 kJ ikhutshwa.
2. Backup. I-Glycogen kunye nesitashi yindlela yokuqokelela izondlo.
3. Zakhiwo. I-Cellulose kunye nezinye iipolyaccharide iimveliso zakha isiseko esisisiseko kwizityalo. Kwakhona, ngokudibanisa neepids kunye neeprotheni, ziyinxalenye yazo zonke izilwanyana zamaselula.
4. Khusela. Ngama-heteropolysaccharides acidic, indima ye-lubricant biological inikezelwe. Bayibeka emacaleni amajoyina abathintelayo aze axoxane kunye nomnye, iimbumba ezinamabhokhwe zempumlo, kunye ne-digestive tract.
5. Anticoagulant. I-carbohydrate, efana ne-heparin, inendawo ebalulekileyo yezinto eziphilayo, oko kukuthi, kuvimbela ukuphuma kwegazi.
6. I-carbohydrates iyimithombo yekhabhoni eyimfuneko yokwenziwa kweproteins, lipids kunye ne-nucleic acids.

Kuba umzimba umthombo omkhulu we-carbohydrates yintlawu-carbohydrates yokutya - i-sucrose, isitashi, i-glucose, i-lactose). I-glucose inokuhlanganiswa kumzimba ngokwawo ukusuka kuma-amino acids, glycerol, lactate kunye ne-pyruvate (gluconeogenesis).

Glycolysis

I-Glycolysis yenye yeendlela ezintathu ezikhoyo ezinokusetyenziswa kwe-glucose oxidation. Kule nkqubo, amandla akhululwa, okugcina agcinwe kwi-ATP nakwi-NADH. Enye yeamolekyuli yayo iqubuka ibe ngama-molecule e-pyruvate.

Inkqubo ye-glycolysis iyenzeka phantsi kwezenzo zezinto ezininzi ze-enzymatic, oko kukuthi, i-catalysts ye-biological nature. I-oxidizer ebaluleke kakhulu i-oksijeni, kodwa kuyafaneleka ukuba uqaphele ukuba inkqubo ye-glycolysis inokuqhutywa ngokungabikho kwe-oksijeni. Uhlobo olufanayo lwe-glycolysis lubizwa ngokuba yi-anaerobic.

I-Glycolysis yoluhlobo lwe-anaerobic yinkqubo yokuhamba nge-glucose oxidation. Ngale glycolysis, i-oxidation ye-glucose ayifuni ngokupheleleyo. Ngaloo ndlela, ngexesha le-oxidation ye-glucose, i-molecule enye ye-pyruvate yenziwa. Ngokweenzuzo zamandla, i-anaerobic glycolysis ayizuzi ngaphantsi kwe-aerobic glycolysis. Nangona kunjalo, ukuba i-oksijeni ingena kwiseli, i-anaerobic glycolysis ingaba yi-aerobic glycolysis, epheleleyo i-oxidation ye-glucose.

Indlela ye glycolysis

Kwinkqubo ye-glycolysis, ukuchithwa kwe-carbon-carbon glucose ezintandathu kwiamoleksi ezimbini ze-carbon-pyruvate zenzeka. Inkqubo yonke iyahlula kwiinqanaba ezi-5 zokulungiselela kunye nezinye ezintlanu, apho i-ATF igcina amandla.

Ngaloo ndlela, i-glycolysis iqhubeka kwizigaba ezibini, ngasinye ngasinye sahlula sibe zigaba ezintlanu.

Isigaba 1 sempendulo ye-oxidization ye-glucose

• Isigaba sokuqala. Kwinqanaba lokuqala, i-glucose i-phosphorylated. Ukusetyenziswa kwe-saccharide kwenzeka nge-phosphorylation kwi-athomu ye-carbon.
• Isigaba sesibini. Kukho inkqubo ye-isomerization ye-glucose-6-phosphate. Kule nqanaba, i-glucose iguqulwa ibe yi-fructose-6-phosphate nge-catalytic phosphogluco isomerase.
• Isigaba sesithathu. I-phosphorylation ye-fructose-6-phosphate. Kule nqanaba, i-fructose-1,6-diphosphate (ebizwa ngokuba yi-aldolase) iveliswa yi-phosphofructokinase-1. Ithatha inxaxheba kwiqela le-phosphoryl ukusuka kwi-adenosine triphosphate kwi-molecule ye-fructose.
• Isigaba sesine. Kule nqanaba, i-aldolase ifakwe. Ngenxa yoko, iamolekyu ezimbini ze-phosphate, i-ketoses kunye nokuqala, zenziwa.
• Isigaba sesihlanu. Isomerization ye-triisophosphates. Kule nqanaba, i-glyceraldehyde-3-phosphate ithunyelwa kwizigaba ezilandelayo zokuhlenga i-glucose. Kule meko, i-dihydroxyacetone iphosphate iguqulwa ibe yindlela ye-glyceraldehyde-3-phosphate. Olu tshintsho lwenziwa phantsi kwezenzo ze-enzymes.
• Isigaba sesithandathu. Inkqubo ye-oxidation ye-glyceraldehyde-3-phosphate. Kule nqanaba, i-molecule ixutywe kunye ne-phosphorylation yayo elandelayo kwi-diphosphoglycerate-1,3.
• Kwisigaba seShenxe. Eli nyathelo liquka ukudluliselwa kwi-1,3-diphosphoglycerate yeqela le-phosphate ukuya kwi-ADP. Kwiphumo lokugqibela kweli nqanaba, i-3-phosphoglycerate ne-ATP zenziwe.

Isigaba sesi-2 - uzalise i-oxidation ye-glucose

• Isigaba sesine. Kule nqanaba, ukuguquka kwe-3-phosphoglycerate kwi-2-phosphoglycerate. Inkqubo yenguqu eyenziwa phantsi kwezenzo ze-enzyme, ezifana ne-phosphoglycerate mutase. Le mpendulo yeekhemikhali ye-oxidation ye-glucose iqhubeka kunye nobukho obunyanzelekile be-magnesium (Mg).
• Isigaba sesithoba. Kule nqanaba izinga lokudlulelwa kwe-2-phosphoglycerate kwenzeka.
• Ishumi lesigaba. Kukho ukudluliselwa kwama-phosphates, okufunyenwe ngenxa yezigaba zangaphambili, kwi-FEP ne-ADP. Ukudluliselwa kwi-ADP yi-phosphoenepiroval. Ukuphendula okunjalo kweekhemikhali kunokwenzeka phambi kwe-magnesium (Mg) kunye ne-potassium (K) ions.

Ngaphansi kweemeko ze-aerobic, yonke inkqubo ifikelela kwi-CO ₂ kunye ne-H ₂ O. Ukulinganisa kwe-glucose oxidation ibukeka kanje:

C ₆ H ₁₂ O ₆ + 6 O ₂ → 6 CO ₂ + 6H ₂ O + 2880 kJ / mol.

Ngaloo ndlela, kwiseli akukho ukuqokelelwa kwe-NADH kwinkqubo yokwakha i-lactate kwi-glucose. Oku kuthetha ukuba inkqubo enjalo i-anaerobic, kwaye iyakwazi ukuqhubeka ngokungabikho kwe-oksijeni. I-oksijeni - eyamkelekileyo yokumkela i-electron, eyadluliselwa kwi-NADH kwindawo yokuphefumula.

Kwinkqubo yokubala ibhalansi yamandla ye-reaction glycolytic, kufuneka ithathelwe ingqalelo ukuba ngalinye isigaba sesigaba sesibini siphinda kabini. Kule nto inokugqitywa ukuba kwisigaba sokuqala iamolekyu ezimbini ze-ATP zichithekile, kwaye ngeli nqanaba lesibini ii-molecule ze-ATP zenziwe yi-phosphorylation ye-substrate uhlobo. Oku kuthetha ukuba ngenxa ye-oxidation nganye ye-molecule ye-glucose, iseli iqokelela i-molecule ye-ATP ezimbini.

Sihlolisise i-oxidation ye-glucose nge-oxygen.

Indlela ye-Anaerobic ye-oxidation ye-glucose

I-Aerobic oxidation yinkqubo ye-oxidation, apho amandla akhululwa khona kwaye okwenzekayo phambi kwe-oksijeni, eyenza njengamkeli wokugqibela we-hydrogen kwindawo yokuphefumula. Umnikeli wamamolekyuli e-hydrogen yindlela echithwe ngayo ye-coenzymes (FADH2, NADH, NADPH), eyenziwa ngexesha lokuphendula ngokukhawuleza kwe-oxidation ye-substrate.

Inkqubo ye-oxidation ye-glucose ye-aerobic type dichotomous yindlela ephezulu ye-glucose catabolism emzimbeni womntu. Olu hlobo lwe-glycolysis lungenziwa kuzo zonke izicubu kunye namalungu omzimba womntu. Isiphumo solu phenduleko kukukhangela kwe-molecule ye-glucose kumanzi kunye ne-carbon dioxide. Umbane olwabiweyo uya kubalwa kwi-ATP. Le nkqubo inokuhlulwa zibe zigaba ezintathu:

1. Inkqubo yokuguqula i-molecule ye-glucose ibe yimiloyidi ye-acid ye-pyruvic. Ukuphendula kwenzeka kwi-cytoplasm yeseli kwaye yindlela ethile yokwahlukana kwe-glucose.
2. Inkqubo yokwakhiwa kwe-acetyl-CoA ngenxa ye-oxidative decarboxylation ye-asiriya ye-pyruvic. Le mpendulo ivela kwi-mitochondria yeselula.
3. Ukuxutywa kwe-acetyl-CoA kumjikelezo weKrebs. Ukuphendula kwenzeka kwi-mitochondria yeselula.

Kwinqanaba ngalinye le nkqubo, i-coenzymes yenziwe iyancitshiswa, ezenziwe nge-enzyme complexes ye-chain chain. Ngenxa yoko, i-ATP yenziwa ngexesha le-oxidation ye-glucose.

Ukuqulunqwa kwama-coenzymes

Ii-coenzymes ezenza kwinqanaba lesibini neyesithathu le-aerobic glycolysis ziya kukhutshwa ngqo kwi-mitochondria yeeseli. Ngokufanayo, i-NADH, eyakhiwa kwi-cytoplasm yeseli ngexesha lokuphendula kwesigaba sokuqala se-aerobic glycolysis, ayinalo ukukwazi ukungena kwimimbrane ye-mitochondria. I-Hydrogen idluliselwa ukusuka kwi-NADH ye-cytoplasm ukuya kwi-mitochondria yeselula ngokusebenzisa i-shuttle cycle. Phakathi kwemijikelezo enjalo kunokwenzeka ukuba ungayiboni enye into ephambili - i-malate-aspartate.

Emva koko, ngoncedo lwe-NADH ye-cytoplasmic, i-oxaloacetate iyancitshiswa ibe yi-malate, leyo leyo ingena kwi-mitochondria yeselula ize ixutywe ngokunciphisa i-NAD ye-mitochondrial. I-Oxaloacetate ibuyela kwi-cytoplasm yeseli ngendlela ye-aspartate.

Iifom eguqulwayo ye-glycolysis

Ukuhamba kwe-glycolysis kunokongezwa ukuba kuhambisane nokukhululwa kwe-1,3 kunye ne-2,3-bisphosphoglycerates. Kule meko, i-2,3-bisphosphoglycerate ingabuyiselwa kwinkqubo ye-glycolysis phantsi kweempembelelo zezinto eziphilayo, kwaye utshintshe uhlobo lwayo kwi-3-phosphoglycerate. Ezi enzyme zidlala indima eyahlukileyo. Ngokomzekelo, i-2,3-bisphosphoglycerate, e-hemoglobin, ikhuthaza ukutshintsha kwe-oksijini ibe ngamathambo, ngaloo ndlela ikhuthaza ukuhlukana kunye nokunciphisa ukuxhatshazwa kwe-oxygen kunye neeseli ezibomvu zegazi.

Isiphelo

Iibhaktheriya ezininzi zinokutshintsha iifom ze-glycolysis kwizigaba ezahlukeneyo. Kunokwenzeka ukunciphisa inani labo elipheleleyo okanye ukuguqula la ma nyathelo njengesiphumo sezenzo ezahlukeneyo ze-enzyme. Ezinye ze-anaerobes zinako ezinye iindlela zokwehla i-carbohydrates. Uninzi lwe-thermophiles lunama-enzymes amabini kuphela, i-enolase ne-pyruvate kinase.

Sihlolisise indlela i-oxidation ye-glucose emzimbeni.