Cov kev cai ntawm cov kev ua ntawm enzymes thiab lawv txoj kev

Raws li ib chav tsev ntawm nyob qhov teeb meem, uas tso cai raws li ib tug txheej ntawm qhib lom systems, lub cell yog lossi sib txuas lus nrog cov sab nraud chaw tshuaj thiab zog. Kom muaj homeostasis nyob rau hauv nws muaj ib tug pab pawg neeg tshwj xeeb tshuaj uas muaj protein ntau cov xwm - enzymes. Qauv, muaj nuj nqi thiab kev tswj ntawm kev ua si ntawm lub enzymes kawm tshwj xeeb ceg biochemistry, enzymology hu ua. Nyob rau hauv no tsab xov xwm, siv pob zeb ua piv txwv, peb yuav xav txog ntau yam mechanisms thiab cov hau kev ntawm regulating cov kev ua ntawm enzymes xam qhovkev rau hauv ntau dua tsiaj thiab tib neeg.

Cov mob uas tsim nyog rau kev pom kev enzyme ua si

Biologically active neeg uas xaiv muaj kev cuam tshuam ob lub assimilation cov tshuaj tiv thaiv thiab cleavage muaj nws catalytic zog nyob rau hauv lub hlwb nyob rau hauv tej yam tej yam kev mob. Piv txwv li, nws yog ib qho tseem ceeb mus nrhiav tawm nyob rau hauv dab tsi yog ib feem ntawm lub cell yuav siv sij hawm qhov chaw ib tug tshuaj txheej txheem, uas yuav enzymes. Vim compartmentation (lub division ntawm lub cytoplasm mus rau lub chaw) antagonistic tshua tshwm sim nyob rau hauv nws ntau qhov chaw thiab organelles.

Yog li, protein synthesis yog nqa tawm nyob rau hauv lub ribosomes thiab lawv cleavage - nyob rau hauv hyaloplasm. Cellular kev ua si kev cai ntawm enzymes uas catalyze biochemical kev tig cev rov qab, tsis tsuas yog muab lub pom tus nqi ndlwg ntawm metabolism, tab sis kuj tsis pub cov tsim ntawm lub zog puas metabolic txoj.

multienzyme complex

Yam ntxwv thiab kev haumxeeb koom haum ntawm lub enzymes, enzymatic ntaub ntawv tsev hlwb. Feem ntau ntawm cov tshuaj uas coj qhov chaw nyob rau hauv nws yog sib xyaw. Yog hais tias nyob rau hauv ib tug multistage tshuaj txheej txheem khoom ntawm tus thawj tshuaj tiv thaiv yog ib tug reactant rau ntxiv, nyob rau hauv cov ntaub ntawv no, lub ntsig txog kev kho ntawm enzymes nyob rau hauv lub cell yog qhia tshwj xeeb xav.

Nws yuav tsum tau nco ntsoov tias enzymes yog los ntawm qhov yooj yim los yog txoj proteins. Thiab lawv rhiab heev rau cellular substrates vim feem ntau mus rau ib tug kev hloov nyob rau hauv nws tus kheej spatial configuration ntawm tertiary los yog quaternary qauv ntawm cov peptide. Enzymes thiab hnov mob rau cov kev hloov tsis tau tsuas yog nyob rau hauv cellular tsis xws li tshuaj nyob tus yeees hyaloplasm, concentration ntawm reactants thiab cov tshuaj tiv thaiv cov khoom, qhov kub thiab txias, tab sis kuj yuav hloov nyob rau hauv lub zos nyob sib ze lub hlwb los yog nyob rau hauv lub extracellular kua.

Yog vim li cas cell muab faib mus rau hauv compartments

Tsim Nyog thiab cov zajlus kom cov tsiaj qus ntaus ntawv tsuas amazing. Qhov no siab siv rau lub neej ces cov yam ntxwv ntawm lub cell. Rau tus paub txog chemist ntshiab heev uas multidirectional enzymatic tshuaj, piv txwv li lub synthesis ntawm glycolysis thiab piam thaj tsis tau mus nyob rau hauv tib lub raj. Yuav ua li cas, ces, rov qab tshwm sim nyob rau hauv cov tshuaj tiv thaiv hyaloplasm ib tug tib cell, uas yog lub substrate rau lawv coj? Nws hloov tawm hais tias lub cellular txheem - lub cytosol, - nyob rau lub antagonistic tshuaj dab yog nqa tawm spatially sib cais thiab raug rho tawm ntaub ntawv loci - compartments. Vim lawv metabolic tshua ntawm ntau dua tsiaj thiab tib neeg yog tswj tshwj xeeb tshaj yog precisely, thiab metabolic khoom uas hloov mus rau hauv daim ntawv no, yooj yim penetrates los ntawm cov phab ntsa hauv cell chaw. Tom ntej no, lawv rov qab los nws cov thawj qauv. Nyob rau hauv tas li ntawd mus rau lub cytosol, cov enzymes uas muaj nyob hauv organelles: ribosomes, mitochondria, nucleus, lysosomes.

Lub luag hauj lwm ntawm enzymes nyob rau hauv lub zog metabolism

Xav txog cov oxidative decarboxylation ntawm pyruvate. Cai ntawm catalytic kev ua ntawm enzymes nws tau tau zoo kawm enzymology. Qhov no biochemical txheej txheem yuav siv sij hawm qhov chaw nyob rau hauv lub mitochondria - dvumembrannyh organelles ntawm eukaryotic hlwb - thiab ib nrab txheej txheem ntawm lub anoxic splitting piam thaj thiab lub Krebs voj voog. Pyruvate dehydrogenase complex - PDH - muaj peb enzyme. Nyob rau hauv ntau dua tsiaj thiab tib neeg txo nws tshwm sim nrog ua concentration ntawm acetyl-CoA thiab Nath, piv txwv li nyob rau hauv cov ntaub ntawv ntawm lwm txoj kev kawm ntawv molecules ntawm acetyl-CoA. Yog hais tias lub cell yuav tsum tau ntau feem ntawm lub zog thiab yuav tsum tau tshiab acceptor molecules rau amplification tshua tricarboxylic acid voj voog, lub enzymes tshuab txais.

Yuav ua li cas yog allosteric inhibition

Cai ntawm cov kev ua ntawm enzymes yuav nqa tawm nrog tshwj xeeb tshuaj - catalytic inhibitors. Tej zaum lawv yuav covalently txuas rau kev loci enzyme, bypassing nws active site. Qhov no ua rau ib tug spatial deformation ntawm lub catalyst qauv thiab txiav entails ib tug txo nyob rau hauv nws cov enzymatic zog. Nyob rau hauv lwm yam lus, muaj yog allosteric kev cai ntawm enzyme ua si. Peb kuj ntxiv hais tias qhov no daim ntawv ntawm catalytic txiav txim xam qhovkev oligomeric enzymes, i.e. cov neeg uas nws molecules muaj ob los yog ntau tshaj polymeric protein subunits. PDH-complex sib tham nyob rau hauv lub yav dhau los title yog cia li muaj peb oligomeric enzyme: pyruvate dehydrogenase, ib tug dehydrogenase thiab degidrolipoil gidrolipoil transatsetilazu.

ntxawg enzymes

Kev tshawb fawb nyob rau hauv Enzymology tsim tseeb hais tias tus nqi ntawm cov tshuaj tshua nyob ob leeg rau lub concentration thiab kev ua si ntawm lub catalyst. Feem ntau cov feem ntau, qhov loj metabolic txoj muaj enzymes uas tswj cov tshuaj tiv thaiv tus nqi ntawm tag nrho nws cov chaw.

Lawv hu ua ntxawg thiab feem ntau cuam tshuam rau cov thawj cov tshuaj tiv thaiv ntawm lub complex, thiab muaj peev xwm koom tau rau hauv feem ntau ntawm qeeb tshuaj dab nyob rau hauv ib tug irreversible cov tshuaj tiv thaiv, los yog koom nrog cov reactants tebchaws ntsiab lus nyob rau hauv ib tug metabolic pathway.

Yuav ua li cas yog lub peptide sis

Ib tug los ntawm txoj kev uas cov kev cai ntawm enzyme ua si tshwm sim nyob rau hauv ib lub cell yog ib tug protein-protein sis raug zoo. Yuav ua li cas yog nws? Ntxawg cov nqaijrog yog merged mus rau lub enzyme molecule, uas lawv ua kom. Piv txwv li, lub adenylate cyclase enzyme nyob rau hauv lub puab nto ntawm lub cell daim nyias nyias thiab tej zaum yuav nrog xws lug li lawm receptor thiab lub peptide pov tseg ntawm nws thiab enzyme. Txij li thaum lub resulting compound lawm receptor hloov nws protein intermediate spatial kev pom zoo, qhov no txoj kev mus pab tau txoj lub catalytic thaj chaw ntawm adenylate cyclase nyob rau hauv biochemistry yog hu ua "kom vim accession ntxawg proteins."

Protomers thiab lawv lub luag hauj lwm nyob rau hauv biochemistry

Qhov no pab pawg neeg ntawm tshuaj, txwv tsis pub hu ua protein kinases, leeb cov kev hloov ntawm lub anion PO ₄ ^3- gidroksogrupp amino acid teej tug mus rau ib tug peptide macromolecule. Cai ntawm cov kev ua ntawm enzymes protomers yuav muab suav hais tias los ntawm peb raws li ib qho piv txwv ntawm cov protein kinase A. Nws molecule - tetramer yog muaj li ntawm ob catalytic thiab ob ntxawg subunits thiab peptide tsis ua raws li cov catalyst li ntev raws li lub ntxawg cheeb tsam rau protomer txuas ib plaub Camp molecule. Qhov no ua rau transformation ntawm lub spatial qauv ntawm ntxawg cov nqaijrog, uas ua rau yus qhov kev tso tawm ntawm ob catalytic tshuab txais protein hais, i.e. dissociation protomers. Yog hais tias cais los ntawm lub ntxawg subunits ntawm Camp molecule, protein kinase tsaug zog complex dua rov qab los ib tetramer, raws li tshwm sim Association catalytic thiab ntxawg peptide hais. Yog li, txoj kev cov kev cai ntawm enzyme ua si sib tham saum toj no muab lawv cov reversible xwm.

Tshuaj kev cai ntawm enzyme ua si

Biochemistry thiab kawm cov mechanisms ntawm kev cai ntawm enzyme ua si, ntsev, dephosphorylation. Lub mechanism ntawm kev cai ntawm enzyme ua si nyob rau hauv cov ntaub ntawv no muaj cov nram qab daim ntawv: amino acid seem ntawm lub enzyme uas muaj OH ^-, hloov lawv cov tshuaj hloov vim raug fosfoproteinfosfataz. Nyob rau hauv cov ntaub ntawv no, tus kho lus amenable mus lub active site ntawm lub enzyme, nyob rau lub enzymes rau ib co yog vim li cas nws yog activating lawv thiab rau lwm leej lwm tus - inhibitory. fosfoproteinfosfataz catalytic zog lawv tus kheej yog tswj los ntawm cov tshuaj hormones nyob rau hauv lem. Piv txwv li, tsiaj cov hmoov txhuv nplej - glycogen - thiab muaj roj nyob rau hauv nruab nrab noj mov lawm cia nyob rau hauv lub mob huam, los yog ntau tshaj precisely, nyob rau hauv lub duodenum nyob rau hauv tus ntawm glucagon - pancreatic enzyme.

Qhov no tus txheej txheem no kho kom zoo los ntawm ntsev ntawm trophic hnyuv enzymes. Nyob rau hauv lub active lub sij hawm ntawm kev zom thaum cov zaub mov nkag mus rau ntawm lub plab rau hauv lub duodenum, glucagon synthesis yog kho kom zoo. Insulin - ib tug pancreatic enzyme uas ua los ntawm cov alpha hlwb ntawm lub islets ntawm Langerhans, - ua num ua ke nrog lub receptor, xws li ntsev ntawm lub tib lub mechanism ntawm digestive enzymes.

ib nrab proteolysis

Raws li koj tau pom, seb kev cai ntawm enzyme ua si nyob rau hauv lub cell varied. Rau enzymes uas yog nyob sab nraum lub cytosol los yog organelles (nyob rau hauv cov ntshav ntshav los yog nyob rau hauv lub mob huam), cov qauv ntawm cov ua kom yog tus txheej txheem ntawm hydrolysis ntawm peptide bonds CO-NH. Nws yuav tsum tau, txij thaum xws enzymes yog tsim nyob rau hauv ib tug tsis nquag daim ntawv. Molecule yog cleaved los ntawm cov enzyme peptide feem thiab tseem yuav tshuav yog kev kawm mus rau kev hloov kho ntawm cov qauv ntawm cov active site. Qhov no ua rau lub fact tias cov enzyme "xws li muaj ib tug ua hauj lwm mob", uas yog, muaj peev xwm cuam tshuam hauv chav kawm ntawm cov tshuaj txheej txheem. Piv txwv li, lub tsaug zog enzyme pancreatic trypsinogen tsis cleaves cov nqaijrog khoom noj khoom haus yuav mus rau qhov duodenum. Nws yuav siv sij hawm qhov chaw nyob rau hauv qhov kev txiav txim ntawm enteropeptidase proteolysis. Tom qab uas lub enzyme yog tshuab txais thiab yog tam sim no hu ua trypsin. Ib nrab proteolysis - tus txheej txheem yog reversible. Nws tshwm sim nyob rau hauv tus neeg mob xws li qhov ua kom ntawm enzymes uas ua txhaum down polypeptides nyob rau hauv cov ntshav txhaws.

Luag hauj lwm ntawm concentration ntawm cov pib ntaub ntawv nyob rau hauv lub cell metabolism

Cai ntawm cov kev ua ntawm cov enzyme substrate muaj saib tej nyob ze subtitle "multienzyme complex." Tus nqi ntawm catalytic tshua noj qhov chaw nyob rau hauv ob peb ua sawv, yog ib co nyob rau ntawm lub xov tooj ntawm molecules ntawm lub pib cov ntaub ntawv uas yog nyob rau hauv hyaloplasm hlwb los yog organelles. Qhov no yog vim lub fact tias cov kev ceev ntawm lub metabolic pathway yog ncaj qha xwm yeem mus rau concentration ntawm cov starting khoom. Qhov loj reactant molecules nyob rau hauv lub cytosol, ntau dua qhov cov kev ceev ntawm tag nrho cov tom ntej tshuaj tshua.

allosteric kev cai

Enzymes uas nws ua si yog tshuaj tsis tau tsuas yog los ntawm lub concentration ntawm pib cov ntaub ntawv, reagents, tab sis kuj cov effector tshuaj, tsiag ntawv los ntawm thiaj li hu ua allosteric kev cai. Feem ntau ntawm cov enzymes uas hais nrog intermediate khoom ntawm metabolism nyob rau hauv lub cell. Vim lub effectors thiab siv cov kev cai ntawm enzyme ua si. Biochemistry pom hais tias cov tebchaw, hu ua allosteric enzymes yog qho tseem ceeb heev rau cov metabolism hauv hlwb, raws li lawv muaj ib tug tsis tshua muaj high rhiab heev rau cov kev hloov nyob rau hauv nws cov homeostasis. Yog hais tias lub enzyme cheeb qhov uas cov tshuaj cov tshuaj tiv thaiv, xws li nws thiaj li nws ceev - nws yog hu ua ib tug tsis zoo effector (inhibitor). Nyob rau hauv lub rov qab cov ntaub ntawv, thaum muaj ib qho kev nce nyob rau hauv cov tshuaj tiv thaiv tus nqi, nws los txog rau lub activator - ib tug zoo effector. Nyob rau hauv feem ntau qhov pib cov ntaub ntawv, i.e. lub reactants nkag mus rau hauv tshuaj cov kev sib tshuam ua si ib lub luag hauj lwm activators. Ntawm cov hoob kawm, cov khoom tsim los ntawm multistage tshua coj raws li inhibitors. Qhov no hom ntawm kev cai lub tsev nyob rau hauv lub kev sib raug zoo ntawm concentration ntawm reactants thiab cov khoom, hu ua heterotrophic.