KumiswaIsayensi

Biochemistry enzyme. Ukwakheka, properties kanye nemisebenzi

Iseli ye zonke izinto eziphilayo ophilayo, izigidi zamakhemikhali zenzeke. Ngamunye wabo kubalulekile, ngakho-ke kubalulekile ukuba singaxoxi ijubane izinqubo yezinto eziphilayo ezingeni eliphezulu. Cishe njalo ukusabela is catalyzed ngu-enzyme yayo. Yiziphi enzyme? Zifeza yiphi indima lapho yezinyoni?

Enzyme. definition

Igama elithi "enzyme" lisuselwa Latin fermentum - imvubelo. Zingase futhi ngokuthi ama-enzyme kusukela esiGrekini zu zyme - "e ukushesha."

Enzyme - izinto eziphila abakhuthele, ngakho iyiphi ukuphendula okwenzeka kuseli, ngeke akwenze ngaphandle kwabo. Lezi zinto zehlela ukwenza njenge yelikhono. Ngakho, noma iyiphi enzyme anezakhi ezimbili eziyinhloko:

1) enzyme ngesivinini ukusabela kwamakhemikhali, kodwa singashi.

2) Inani njalo yakhoibrium asishintshi, kodwa nje yashesha uhamba phambili ekufezeni lokhu value.

Enzyme kusheshiswe ukusabela kwamakhemikhali izinkulungwane, futhi kwezinye izimo, izikhathi eziyisigidi. Lokhu kusho ukuthi ukungabi khona kohlelo enzyme zonke izinqubo intracellular uye ngacishe ngayeka, futhi ingqamuzana uqobo uyafa. Ngakho-ke, indima enzyme njengoba ezisebenzayo kuphezulu.

A ezihlukahlukene enzyme kwenza kube nokwenzeka ukuba ehlukahlukene alawule cell umzimba. Kunoma kubangela ukusabela onengxenye amakilasi eziningi ezahlukene enzyme. yelikhono eziphilayo abe selectivity eliphezulu ngokusebenzisa conformation ethize engqamuzaneni. T. Ukuze. Ezimweni eziningi enzyme kukhona amaprotheni ngokwemvelo, zingabantu isakhiwo ephakeme noma quaternary. Isizathu uphinda ngokucacile engqamuzaneni.

Umsebenzi enzyme kuseli

Umsebenzi oyinhloko enzyme - ukusheshisa elihambisana ukuphendula. Noma yimuphi izinqubo wendlale, kusukela yokubola i-hydrogen peroxide kanye glycolysis ophela, kudinga khona kulethe begazi.

ukusebenza kahle enzyme izuzwe ngokucacile okusezingeni eliphezulu kumuntu substrate ethize. Lokhu kusho ukuthi kulethe ungenziwa kuphela ukusheshisa ukuphendula ezithile futhi kusaba khona, ngisho ayefana kakhulu. Ngu degree of ngokucacile of enzyme, okulandelayo amaqembu:

1) enzyme nge ngokucacile ngokuphelele lapho catalyzed ukusabela olulodwa eyodwa kuphela. Ngokwesibonelo, collagenase digests le-collagen, futhi maltase uhlaba maltose.

2) enzyme nge ngokucacile isihlobo. Lokhu kuhlanganisa izinto ezingaba catalyze isigaba esithile ukusabela, isibonelo, cleavage hydrolytic.

umsebenzi biocatalyst iqala uxhumano site yayo esisebenzayo substrate. Ngesikhathi esifanayo ukukhuluma mayelana nokuxhumana aphelele efana ukukhiya nokhiye. Lokhu kusho ukufana ngokugcwele substrate ukuba yakha isikhungo esebenzayo, okuyinto wenza sikwazi ukusheshisa ukuphendula.

Isinyathelo esilandelayo siqukethe ngokuhamba ukusabela. Isivinini salo inyuka ngo isenzo eziyinkimbinkimbi enzyme. Ekugcineni, sithola ama-enzyme, okuyinto lihlotshaniswa imikhiqizo ukuphendula.

Isigaba sokugcina - ukususa imikhiqizo ukuphendula kusuka enzyme, ngemva kwalokho isayithi asebenzayo waphinda iba mahhala kwenye operation.

Schematically, umsebenzi enzyme esigabeni ngasinye singatlolwa bunjesi:

1) S + E -> SE

2) SE -> SP

3) SP -> S + P, lapho S - kuyinto substrate, E - enzyme, kanye P - umkhiqizo.

Ukwahlukaniswa enzyme

Emzimbeni womuntu, ungathola inombolo enkulu enzyme. Zonke ulwazi mayelana nemisebenzi yabo kanye nomsebenzi abangu systematized, futhi ngenxa yalokho kwaba khona ngezigaba ezivamile, lapho ungakwazi kalula ukuthi liyini kulethe ethile. Nazi amakilasi ayisithupha eziyisisekelo enzyme, kanye ezinye izibonelo subgroups.

  1. Oxidoreductase.

Enzyme alesi sigaba catalyze ukusabela redox. Ubude walulama sub-ngamaqembu 17. Oxidoreductases ngokuvamile non-amaprotheni ingxenye enikeziwe namavithamini noma cha heme.

Phakathi oxidoreductases ngokuvamile bathole subgroups ezilandelayo:

a) Dehydrogenase. enzyme Biochemistry-dehydrogenase is sakhathala salokhu sinamathele ama-athomu ye-hydrogen kanye nokudlulisela kwenye substrate. Lesisigaba kuvamile kakhulu ukusabela emishinini yokuphefumula, inqubo ye-photosynthesis. Njengengxenye dehydrogenase kuyadingeka ekhona ngesimo coenzyme nad / NADH noma flavoproteins mkhuba / FMN. Ngokuvamile kukhona metal ion. Izibonelo zibandakanya enzyme ezifana tsitohromreduktazy, dehydrogenase pyruvate, dehydrogenase isocitrate, futhi enzyme abaningi isibindi (lactate dehydrogenase, glutamate dehydrogenase, nokunye. D.).

b) oxidases. Inombolo yama-enzymes catalyze kwalokho oxygen hydrogen, lapho imikhiqizo ukuphendula kungaba amanzi noma i-hydrogen peroxide (H 2 0, H 2 0 2). Izibonelo uketshezi cytochrome oxidase, tyrosinase.

c) peroxidase futhi catalase - enzyme ukuthi catalyze H 2 O 2 noqhekeko namanzi ne-oksijini.

g) oxygenase. Lezi biocatalysts ukusheshisa-mpilo okunamathiselwe ku substrate. Dofamingidroksilaza - esinye sezibonelo enzyme ezinjalo.

2. Transferases.

Target enzyme yalesi qembu ukudluliselwa ezizivelelayo kusukela Ingqikithi ketshezi donor kumamukeli.

a) methyltransferase. DNA methyltransferase - enzyme ukhiye ezilawula inqubo DNA ukufanisana. Methylation nucleotide inendima enkulu e ukulawulwa nucleic umsebenzi acid.

b) acyltransferase. Enzyme lokhu iqeqebana kuthiwa zithutha komunye-molecule ngokwenzeka kwelinye iqembu acyl. Izibonelo acyltransferases: lecithin-cholesterol acyltransferase (ithwala iqembu obusebenzayo nge acid okunamafutha ku cholesterol), lizofosfatidilholinatsiltransferaza (acyl iqembu udluliselwa lysophosphatidylcholine).

c) aminotransferases - enzyme abathintekayo ukuguqulwa amino acid. Izibonelo uketshezi aminotransferase alanine okuyinto catalyzes synthesis alanine kusukela pyruvate futhi glutamate ngokudlulisela iqembu acid.

g) phosphotransferase. Enzyme catalyze ukwengeza le-iqembu sub leqembu phosphate. Enye kinase igama phosphotransferase, evame kakhulu. Izibonelo zibandakanya enzyme ezifana hexokinase futhi aspartate, okuyinto anamekwe izinsalela hexose phosphate (ikakhulukazi glucose), kanye aspartic acid , ngokulandelana.

3. Hydrolases - isigaba enzyme ukuthi catalyze le cleavage izibopho e-molecule, kulandele ukwengeza amanzi. Izinto ukuthi singabakaNkulunkulu leli qembu - main enzyme wokugaya ukudla.

a) esterases - ukuphula izibopho ester. Isibonelo - lipases ukuthi sokudiliza amafutha.

b) glycosidases. Biochemistry enzyme salolu chungechunge itholakala ukubhujiswa izibopho glycoside ka polymers (oligosaccharides futhi polysaccharides). Izibonelo: Amylase, sucrase, maltase.

c) peptidase - enzyme ukuthi catalyze ukuwohloka amaprotheni ku-amino acid. enzyme ezihlobene peptidase-ezifana pepsin, trypsin, chymotrypsin, karboiksipeptidaza.

g) Amidases - ninamathele amide izibopho. Izibonelo: .. Arginase, urease, glutaminase njll Abaningi amidase enzyme atholakala umjikelezo ornithine.

4. Lyases - enzyme i imisebenzi efana hydrolases Kodwa kule cleavage izibopho e molecule asiqediwe amanzi. Enzyme alesi sigaba njalo ingxenye non-amaprotheni ingxenye, isibonelo, ngesimo amavithamini B1 kanye B6.

a) decarboxylase. Lezi enzyme isinyathelo C-C isibopho. Izibonelo glutamic acid decarboxylase noma decarboxylase pyruvate.

b) hydratase futhi dehydratase - enzyme ukuthi catalyze le cleavage C-O izibopho.

c) amidine-lyases - kokubhubhisa C-N isibopho. Isibonelo: argininsuktsinatliaza.

g) R-O lyase. enzyme okunjalo kuvame wajinge wanamatsela iqembu phosphate kusuka impahla substrate. ISIBONELO: cyclase adenylyl.

Biochemistry enzyme esekelwe isakhiwo sabo

Ikhono enzyme ngalinye kunqunywa ngazinye, kuphela nesakhiwo sakhe esingokwemvelo. Noma yimuphi enzyme - ngokuyinhloko amaprotheni, futhi isimo sawo futhi degree of ukusonga sinendima ebalulekile ekunqumeni umsebenzi walo.

biocatalyst ngalinye libhekene khona isikhungo esebenzayo, okuyinto yena, ihlukaniswe ezindaweni eziningana abahlukene obusebenzayo:

1) Catalytic Centre - isifunda ekhethekile amaprotheni, lapho enzyme ukunamathela substrate. Kuye conformation amaprotheni-molecule isikhungo okhanda amanye amathuba kungathatha ezihlukahlukene amafomu, okumele luhambisane substrate kanye ukukhiya nokhiye. isakhiwo esinjalo eziyinkimbinkimbi uyachaza ukuthi kungani amaprotheni enzyme lisasesimweni ephakeme noma quaternary.

2) Adsorption Centre - ukhonza njengelungu "umnikazi". Lapha, okokuqala zokuxhumana senzeka phakathi engqamuzaneni enzyme kanye engqamuzaneni substrate. Nokho, ukuxhumana esakha isikhungo adsorption, enganamandla kakhulu, futhi ngaleyo ndlela yokusabela okhanda amanye amathuba esethola kulesigaba Lesiphakeme.

3) kungenzeka izikhungo Allosteric etholakala maphakathi iyasebenza, futhi kuyo yonke ebusweni enzyme. Umsebenzi wawo - ukulawulwa enzyme. Regulation senzeka nge molecule inhibitor futhi activators molecule.

I amaprotheni Activator sesibopho ukuthobisa i-molecule ye-enzyme, shesha ukusebenza kwawo. Inhibitors, kunalokho, zivimbela umsebenzi okhanda amanye amathuba, futhi lokhu kwenzeke ngezindlela ezimbili: kuphakathi kokuthi i-molecule ye sibopha ukuthi esifundeni allosteric maphakathi nendawo esebenzayo ye-enzayimu (okusithiyayo yokuncintisana) noma kuxhunywe kwenye esifundeni amaprotheni (okusithiyayo noncompetitive). okusithiyayo Competitive kubhekwa ngendlela ephumelela kakhudlwana. Ngemva isikhala ngaleyo ndlela avaliwe substrate sesibopho ukuthobisa enzyme, kanye le nqubo kungenzeka kuphela uma nje kwaqondana cishe ngokuphelele engqamuzaneni inhibitor futhi ukwakha isikhungo asebenzayo.

Enzyme ngokuvamile akunalo amino acid, kodwa futhi ezinye izinto eziphilayo futhi wezinto ezingaphili. Ngakho, apoenzyme letimele - proteinaceous ingxenye coenzyme - moiety organic cofactor - wezinto ingxenye. Coenzyme kungenzeka amelwe ulgevodami, amafutha, acid nucleic, amavithamini. Ngakwelinye ihlangothi, co-factor - ngokuvamile ukusekela metal ion. umsebenzi enzyme kunqunywa oyiyo: izinto engeziwe kufakwe Ukwakheka, ukushintsha izakhiwo okhanda amanye amathuba. izinhlobo ezahlukene enzyme - kuwumphumela inhlanganisela yazo zonke lezi zici akha eziyinkimbinkimbi.

WokuLawula umsebenzi enzyme

Enzyme nomongo eziphila abakhuthele akudingekile umzimba njalo. Biochemistry enzyme ngukutsi kungathi esimweni ngamangqamuzana aphilayo ngokweqile catalysis umonakalo. Ukuvimbela imiphumela eyingozi emzimbeni enzyme ezidingekayo ngandlela-thile lokulawula umsebenzi wabo.

T. Ukuze. Enzyme kukhona amaprotheni ku bemvelo, basuke kalula ubhujiswe ngamazinga ashisa kakhulu. inqubo denaturation esethola, kodwa kungase kakhulu ezithinta ketshezi.

pH nakho kufeza indima ebalulekile ukulawulwa. Ubuningi umsebenzi enzyme ibizwa ngokuvamile obaphawuleka pH kokungathathi hlangothi (7,0-7,2). Ubuye enzyme ukuthi isebenze kuphela ngaphansi kwezimo esidi noma kuphela ane-alikhali. Ngakho, ngo-lysosomes yeselula zigcinwe pH ongaphakeme, lapho umsebenzi maximal enzyme hydrolytic. Esimeni contact ngephutha ne cytoplasm, lapho imvelo is closer kuze hlangothi, umsebenzi wabo uzokwehla. Ukuvikelwa okunjalo kusukela "samopoedaniya" isekelwe izici hydrolase.

Kuhle kokusho ngokubaluleka coenzyme futhi cofactor lichaza ekwakheni enzyme. Ukuba khona amavithamini noma insimbi ion kakhulu ezithinta ukusebenza ezinye enzyme ethize.

Ngesilwane esifuywayo enzyme

Zonke enzyme of umzimba abizwa ngokuthi ama ngokuvumelana bengabakaJehova yimiphi amakilasi, kanye substrate ngawo zisabela. Ngezinye izikhathi i-ngesilwane esifuywayo ehlelekile isetshenziswe owodwa kodwa washo emibili ka substrate esihlokweni.

Izibonelo amagama ezinye enzyme:

  1. Isibindi enzyme: lactate degidrogen aza-glutamate-aza-degidrogen.
  2. Igama eliphelele esihleliwe enzyme: lactate + nad-aza -oksidoredukt.

Ilondolozwe Kahle nokuyize amagama, okuyinto musa zithobele imithetho ngesilwane esifuywayo. Izibonelo ama-enzyme: trypsin, chymotrypsin, pepsin.

Inqubo ye-zamagama enzyme

Imisebenzi yama-enzyme zinqunywa ngisho ezakhini zofuzo. Kusukela molecule ngokwengxenye enkulu -. Amaphrotheni, futhi zamagama salo nse izinqubo of umbhalo kanye wokuhumusha.

Synthesis enzyme kwenzeka kanje. Ekuqaleni, DNA ukufunda ulwazi mayelana enzyme oyifunayo ukwakha mRNA. Isilayezi RNA buqonda zonke amino acid ayingxenye enzyme. Regulation enzyme futhi kungenzeka ezingeni DNA, uma umkhiqizo ukusabela catalyzed ngokwanele isakhi sofuzo umbhalo uyama futhi ngokuphambene nalokho, uma kukhona isidingo umkhiqizo, owenza usebenze inqubo umbhalo.

Uma mRNA yakhululwa cytoplasm, esigabeni esilandelayo - ukusakaza. On ribosomes reticulum endoplasmic kwemiqondo uchungechunge eyinhloko ehlanganisa amino acid exhumene ngu peptide izibopho. Nokho, i-molecule ye amaprotheni ku isakhiwo eyinhloko Awukwazi ukwenza umsebenzi walo enzymatic.

Umsebenzi enzyme luncike amaprotheni izakhiwo. EPS Same amaprotheni kwenzeka ezimazombe, kanjalo ukwakha isakhiwo sokuqala yesibili bese ephakeme. I synthesis ezinye enzyme wayeka kulesi sigaba, kodwa ukuthuthukisa umsebenzi kulethe ngokuvamile okunamathiselwe ezidingekayo futhi cofactor coenzyme.

Ezindaweni ezithile we reticulum endoplasmic iza unamathisele izingxenye eziphilayo enzyme: ushukela, acid nucleic, amafutha kanye amavithamini. Ezinye enzyme ayikwazi ukusebenza ngaphandle ukuba khona coenzyme.

Cofactor linendima ebalulekile ekwakhiweni isakhiwo quaternary amaprotheni. Abanye imisebenzi yama-enzymes kuphela lapho inhlangano amaprotheni lesizinda etholakalayo. Ngakho-ke kubaluleke kakhulu ukuba khona quaternary yabo isakhiwo lapho isixhumanisi yokuxhuma phakathi amaningi amaprotheni globules kuyinto ion metal.

amafomu amaningi enzyme

Kunezimo lapho kudingeka khona enzyme eziningana ukuthi catalyze ukusabela okufanayo, kodwa ihluke nomunye ezicini ezithile. Ngokwesibonelo, ama-enzyme ingasebenza ngesikhathi degrees 20, kodwa ngaleso 0 degrees, ngeke ukwazi ukwenza umsebenzi wawo ngendlela yena. Okufanele ukwenze uma ubhekene nesimo esinjena, umzimba eziphilayo ngaphansi kwamazinga okushisa aphansi?

Lenkinga ibuye kalula ixazululwe khona enzyme eziningana ukuthi catalyze ukusabela okufanayo, kodwa ezimweni ezahlukene zokusebenza. Kunezinhlobo ezimbili zama-amafomu amaningi enzyme:

  1. Isoenzymes. amaprotheni ezinjalo okubhalwe ufuzo ezahlukahlukene, yakhiwa acid ezahlukene acid, kodwa catalyze ukusabela okufanayo.
  2. Iqiniso amafomu amaningi. Lezi amaprotheni alotshwa kusukela isakhi sofuzo efanayo, kodwa kwenzeka ku ribosomes ukuguqulwa peptides. Ngesikhathi okukhiphayo ekhiqizwa izinhlobo eziningana enzyme efanayo.

Ngenxa yalokho, kwakhiwa izinhlobo eziningi uhlobo lokuqala ezakhini zofuzo, lapho yesibili - kwi post-Translational.

okusho enzyme

Ukusetshenziswa enzyme imithi zehla nempikiswano imithi emisha, njengengxenye lapho izinto kakade nenani kwesokudla. Ososayensi azikakutholi ngendlela ukuze sikhuthaze zamagama olungekho enzyme emzimbeni, kodwa manje esakazwa izidakamizwa ezingaba ezakha isikhathi kusimo yabo.

enzyme abahlukahlukene e yeseli catalyze inqwaba ukusabela eziphathelene nokugcinwa zokuphila. Enye yalezi abameleli kuthiwa enizmov nucleases iqembu: endonuclease futhi exonuclease. Umsebenzi wabo iwukuhlale ezingeni njalo acid nucleic esitokisini, ukususwa DNA alimele RNA.

Ungakhohlwa mayelana lo mkhuba igazi ekunqandeni. Njengoba isilinganiso ngempumelelo yokuvikela, inqubo ilawulwa eziningi enzyme. Chief phakathi kwazo thrombin, oguqula ngasebenzi amaprotheni fibrinogen ku fibrin asebenzayo. ngentambo yayo kudala uhlobo senethiwekhi occludes isitsha ukulimala indawo, kanjalo uvimbele ukudala ezinye ngokweqile ukopha.

Enzyme asetshenziswa winemaking, uthuthuva, ukukhiqizwa imikhiqizo eminingi yobisi. Nokho, utshwala kusukela imvubelo glucose ingasetshenziswa, ngoba nesenzakalo ngempumelelo le nqubo futhi kukhishwe ngokwanele babo.

Amaqiniso ethakazelisayo okuyinto ningamazi

- Zonke enzyme omzimba abe yisisindo esikhulu - 5,000 ukuze 1,000,000 Da. Lokhu kungenxa yokuba khona amaprotheni ku-molecule. Ukuze uqhathanise, isisindo yamangqamuzana glucose - 180 Yebo, ne-carbon dioxide - ingqikithi 44 Yebo.

- Kuze kube manje, wavula ezingaphezu kuka-2000 enzyme ukuthi zitholakala amaseli eziphilayo ezihlukahlukene. Nokho, iningi lalezi izinto ziya akukaqondwa ngokugcwele.

- Umsebenzi enzyme isetshenziselwa ukuthola ngempumelelo egeza izimpushana. Lapha, ama-enzyme ukufeza indima efanayo emzimbeni: besephula phansi udaba eziphilayo, futhi lokhu impahla kuyasiza ukulwa izindawo. Kunconywa ukusebenzisa yokuwasha enjalo ezingeni lokushisa hhayi ephakeme kunaleyo degrees 50, kungenjalo kungase ukuya inqubo denaturation.

- Ngokusho izibalo, u-20% abantu emhlabeni wonke uhlushwa ukuntuleka yimiphi enzyme.

- Mayelana izakhiwo enzyme eyaziwa isikhathi eside, kodwa kuphela 1897, abantu baqaphela ukuthi hhayi imvubelo, futhi sicashunwa amaseli wabo ingasetshenziswa ukuvutshelwa ushukela ube utshwala.

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