Biochemistry enzymes. Structure, Properties da ayyuka

A cell kowane mai-rai kwayoyin, miliyoyin sinadaran halayen faru. Kowane daga cikinsu yana da muhimmanci, saboda haka yana da muhimmanci domin tabbatar da gudun nazarin halittu tafiyar matakai a wani babban matakin. Kusan kowace dauki aka catalyzed ta enzyme. Menene enzymes? Mene ne rawar da suka taka a cikin wani keji?

Enzymes. definition

Kalmar "enzyme" da aka samu daga Latin fermentum - yistin. Su ƙila za a kira enzymes daga Greek en zyme - "a leaps da haddi."

Enzymes - ilimin aiki abubuwa, don haka duk wani dauki abin da ke faruwa a cikin cell, ba zai iya yi ba tare da su. Wadannan mahadi yi aiki a matsayin catalysts. Haka kuma, wani enzyme biyu main Properties:

1) enzyme accelerates da biochemical dauki, amma shi ne bai ƙone ba.

2) A darajar da ma'auni m ba ya canja, amma kawai accelerates da nasara ta wannan darajar.

Enzymes bugun up biochemical halayen a cikin dubbai, da kuma a wasu lokuta, sau miliyan. Wannan yana nufin cewa a cikin rashi na enzyme tsarin duk kwayuka matakai ya kusan tsaya, da kuma cell kanta mutu. Saboda haka, rawar da enzymes kamar yadda aiki sinadaran ne high.

A iri-iri na enzymes sa ya yiwu don sarrafa tsara cell metabolism. A wani cascade da halayen da shan kashi da yawa daban-daban azuzuwan na enzymes. Halittu catalysts da wani babban selectivity ta musamman conformation da kwayoyin. T. Don. A mafi yawan lokuta enzymes masu gina jiki a cikin yanayi, su sunã a cikin manyan ko quaternary tsarin. Dalilin shi ne sake da bayani dalla-dalla na kwayoyin.

The aiki na enzymes a cikin cell

Babban aiki na enzyme - hanzari m dauki. Duk wani cascade matakai, tun bazuwar na hydrogen peroxide da kuma kawo karshen glycolysis, na bukatar kasancewar wani nazarin halittu kara kuzari.

Proper aiki na enzymes cimma high bayani dalla-dalla don takamaiman substrate. Wannan yana nufin cewa mai kara kuzari iya kawai hanzarta wasu dauki kuma babu more, ko da sosai kama. By mataki na bayani dalla-dalla na enzyme, wadannan kungiyoyin:

1) enzymes tare da cikakken bayani dalla-dalla a lokacin da catalyzed ta daya kawai guda dauki. Alal misali, collagenase digests da collagen, kuma maltase cleaves maltose.

2) enzymes da zumunta bayani dalla-dalla. Wannan ya hada da abubuwa da za su iya tsara wani aji na halayen, misali, hydrolytic tsakiyan nonon.

biocatalyst aiki ta fara da connection ta aiki site zuwa substrate. A lokaci guda magana game da karin hulda kama da wani kulle da kuma key. Wannan yana nufin cikakken wasa tare da substrate Forms da aiki cibiyar, wanda ya sa ya yiwu don hanzarta da dauki.

A mataki na gaba ya kunshi a cikin shakka daga cikin dauki. Its gudun ƙaruwa da mataki na enzyme hadaddun. A ƙarshe, mun samu da enzyme, wanda ake dangantawa da dauki kayayyakin.

Karshe mataki - don cire dauki kayayyakin daga enzyme, bayan da aiki site sake zama free ga wani aiki.

Schematically, aikin da enzyme a kowane mataki za a iya rubuta kamar:

1) S + E -> SE

2) SE -> SP

3) SP -> S + P, inda S - ne substrate, E - da enzyme, da kuma P - samfurin.

rarrabuwa na enzymes

A cikin jikin mutum, za ka iya samun babban adadin enzymes. All ilmi game da su ayyuka da kuma aikin da aka systematized, kuma a sakamakon akwai wani na kowa rarrabuwa, ta hanyar da ka iya sanin abin da yake a musamman mai kara kuzari. Ga shida na asali azuzuwan na enzymes, kazalika da wasu misalai na subgroups.

1. Oxidoreductase.

Enzymes wannan aji tsara redox halayen. Total gano 17 sub-kungiyoyin. Oxidoreductases yawanci maras gina jiki rabo bayar bitamin ko heme.

Daga cikin oxidoreductases ne sau da yawa samu da wadannan subgroups:

a) Dehydrogenase. Biochemistry-dehydrogenase enzyme da aka lazimta a kansu hydrogen kwayoyin zarra da canja wurin shi zuwa wani substrate. Wannan subgroup ne ya fi kowa a cikin halayen da numfasawa, photosynthesis. Kamar yadda wani ɓangare na dehydrogenase ne dole ba a cikin nau'i na coenzyme nad / NADH ko flavoproteins fad / FMN. Sau da yawa akwai karfe ions. Misalan sun ha] enzymes kamar tsitohromreduktazy, pyruvate dehydrogenase, isocitrate dehydrogenase, kuma ma da dama hanta enzymes (lactate dehydrogenase, glutamate dehydrogenase, da sauransu. D.).

b) oxidases. A yawan enzymes tsara Bugu da kari na oxygen zuwa hydrogen, inda dauki kayayyakin iya zama ruwa ko hydrogen peroxide (H ₂ 0, H ₂ 0 _2). Misalai na enzymes cytochrome oxidase, tyrosinase.

c) peroxidase da catalase - enzymes cewa tsara da bazuwar H ₂ Ya ₂ ga ruwa da oxygen.

g) oxygenase. Wadannan biocatalysts hanzarta oxygen da aka makala ga substrate. Dofamingidroksilaza - daya daga cikin misalai na irin wannan enzymes.

2. Transferases.

Target enzymes na wannan kungiya shi ne canja wuri na radicals daga dũkiyar bayarwa abu da mai karɓa.

a) methyltransferase. DNA methyltransferase - key enzymes cewa sarrafa aiwatar da DNA kwafi. Methylation nucleotides taka wata muhimmiyar rawa a cikin tsari na nucleic acid aiki.

b) acyltransferase. Enzymes da wannan subgroup suna hawa daga daya kwayoyin zuwa wani acyl kungiyar. Misalai acyltransferases: lecithin-cholesterol acyltransferase (daukawa aikin kungiyar tare da m acid a kan cholesterol), lizofosfatidilholinatsiltransferaza (acyl kungiyar da aka canjawa wuri zuwa lysophosphatidylcholine).

c) aminotransferases - enzymes cewa suna da hannu a cikin hira da amino acid din. Misalai na enzymes alanine aminotransferase wanda catalyzes kira na alanine daga pyruvate da glutamate ta canja wani amino kungiyar.

g) phosphotransferase. Enzymes tsara Bugu da kari na wannan sub-rukuni na phosphate kungiyar. Wani sunan phosphotransferase kinase, shi ne fiye da na kowa. Misalan sun ha] enzymes kamar hexokinase da aspartate, wanda aka haɗe zuwa hexose phosphate sharan (kagaggun glucose), da kuma aspartic acid , bi da bi.

3. Hydrolases - wani aji na enzymes cewa tsara da tsakiyan nonon na shaidu a cikin DNA, bi da Bugu da kari na ruwa. Abubuwa da na wannan kungiyar - babban narkewa kamar enzyme.

a) esterases - warware ester shaidu. Misali - lipases cewa karya saukar fats.

b) glycosidases. Biochemistry enzymes daga cikin wannan jerin ta'allaka a cikin halakar da glycoside shaidu na polymers (oligosaccharides da polysaccharides). Misalai: amylase, sucrase, maltase.

c) peptidase - enzymes cewa tsara da fashewa sunadaran amino acid. Peptidase alaka enzymes kamar pepsin, trypsin, chymotrypsin, karboiksipeptidaza.

g) Amidases - manne amide shaidu. Misalai: .. Arginase, urease, glutaminase da dai sauransu da yawa amidase enzymes da ake samu a ornithine sake zagayowar.

4. Lyases - enzymes ga ayyuka kama hydrolases, duk da haka a cikin tsakiyan nonon mata na shaidu a cikin kwayoyin ba cinye ruwa. Enzymes wannan aji ko da yaushe suna da wani ɓangare na ba-gina jiki sashi, misali, a cikin nau'i na bitamin B1 da kuma B6.

a) decarboxylase. Wadannan enzymes aiki a kan C-C bond. Misalai ne glutamic acid decarboxylase ko pyruvate decarboxylase.

b) hydratase da dehydratase - enzymes cewa tsara da tsakiyan nonon na C-O shaidu.

c) A amidine-lyases - lalata C-N bond. Misali: argininsuktsinatliaza.

g) R-O lyase. Irin wannan enzymes yawanci cleaved a phosphate kungiyar daga substrate abu. MISALI: adenylyl cyclase.

Biochemistry na enzymes bisa laákari da tsarin

Da ikon da kowane enzyme ne m da mutum, kawai ya muhimmi tsarin. Duk wani enzyme - shi ne da farko gina jiki, da kuma da tsarin da kuma digiri na nadawa taka muhimmiyar rawa a kayyade ta aiki.

Kowane biocatalyst ne halin da gaban da aiki cibiyar, wanda, bi da bi, ne zuwa kashi da dama jinsin aikin yankunan:

1) catalytic Center - musamman yankin na gina jiki, a cikin abin da enzyme riko da substrate. Dangane da conformation da sunadarin catalytic cibiyar iya daukar salo da dama, abin da ya kamata dace da substrate kazalika da kulle da kuma key. Irin wannan hadadden tsarin dalilin da ya sa enzyme gina jiki shi ne a cikin manyan ko quaternary jihar.

2) adsorption Center - hidima a matsayin "mariƙin". A nan, na farko na dukkan sadarwa faruwa tsakanin enzyme kwayoyin da substrate kwayoyin. Duk da haka, dangane da siffofin da adsorption cibiyar, sosai rauni, kuma ta haka ne da catalytic dauki reversible a wannan mataki.

3) Allosteric cibiyoyin iya located a cikin aiki cibiyar, da kuma dukan surface na enzyme. Su aiki - tsari na enzyme. Regulation faruwa via kwayoyin hanawa da kuma activators kwayoyin.

A activator sunadaran dauri ga enzyme DNA, hanzarta aiki. Hanawa, a akasin haka, hana catalytic ayyuka, da kuma wannan na iya faruwa a hanyoyi biyu: ko dai da kwayoyin ta ɗaure ga allosteric cibiyar yankin na aiki cibiyar na enzyme (m hanawa) ko shi ne a haɗe zuwa wani yankin na gina jiki (noncompetitive hanawa). M hanawa an dauki mafi tasiri. Bayan haka rufaffiyar sarari ga substrate dauri ga enzyme, kuma da wannan tsari ne kawai zai yiwu a yanayin saukan kusan cikakken daidaituwa na hanawa kwayoyin da kuma samar da wani aiki cibiyar.

Enzyme sau da yawa ba kunshi amino acid, amma kuma wasu kwayoyin da inorganic abubuwa. Haka kuma, ya zama ruwan dare apoenzyme - proteinaceous rabo coenzyme - kwayoyin moiety da cofactor - inorganic part. Coenzyme iya wakilta ulgevodami, fats, nucleic acid, bitamin. Bi da bi, da co-factor - shi ne sau da yawa wani goyon bayan karfe ions. Enzyme aiki ne m da da tsarin: Ƙarin abubuwa kunshe a cikin abun da ke ciki, musanyãwa catalytic Properties. Daban-daban iri enzymes - shi ne sakamakon mai hade da duk wadannan abubuwan ta samar da hadaddun.

Regulation na aikin enzymes

Enzymes matsayin ilimin aiki abu ne ba ko da yaushe dole ga jiki. Biochemistry na enzymes shi ne cewa su yiwu a yanayin saukan wuce kima catalysis cũta rayayyun tantani. Don hana cutarwa effects a jiki enzymes zama dole to ko ta yaya gwada aikinsu.

T. Don. Enzymes ne gina jiki a cikin yanayi, suna readily halakar a high yanayin zafi. denaturation tsari ne reversible, amma shi iya muhimmanci shafar abu.

PH kuma taka muhimmiyar rawa a cikin tsari. Matsakaicin enzyme aiki ne kullum lura a tsaka tsaki PH (7,0-7,2). Har ila yau yana da enzymes cewa aiki ne kawai a karkashin acidic yanayi ko kawai a alkaline. Saboda haka, a cikin salon salula lysosomes kiyaye low PH, a da iyaka aiki na hydrolytic enzymes. A taron na mai haɗari lamba tare da cytoplasm, inda yanayi ne mafi kusanta zuwa tsaka tsaki, su aiki za su ragu. Irin wannan kariya daga "samopoedaniya" dogara ne a kan siffofin da hydrolase.

Yana da daraja ambata game da muhimmancin coenzyme da cofactor a cikin abun da ke ciki na enzymes. A gaban bitamin ko karfe ions muhimmanci shafi aiki na wasu takamaiman enzymes.

Nomenclature na enzymes

All enzymes na jiki da ake kira bisa ga na wa wani daga cikin azuzuwan, kazalika da substrate tare da wanda suka amsa. Wani lokacin da na din-din-din nomenclature amfani ba daya amma biyu daga cikin substrate a cikin suna.

Misalan sunayen wasu enzymes:

1. Hanta enzymes: lactate degidrogen Aza-glutamate-Aza-degidrogen.
2. Cikakken din sunan enzyme: lactate + nad-Aza -oksidoredukt.

Kiyaye su da kuma maras muhimmanci sunayen, wanda ba bi da dokokin nomenclature. Misalai ne narkewa kamar enzymes: trypsin, chymotrypsin, pepsin.

A tsari na kira na enzymes

The ayyuka na enzymes aka ƙaddara ko da a kayyade matakin. Tun da kwayoyin ne da kuma manyan -. Protein, da kuma ta kira shi ne daidai kamar tafiyar matakai na kwafi da kuma fassara.

Kira enzymes auku kamar haka. Da farko, DNA karanta bayanai game da so enzyme ta samar da mRNA. Manzon RNA encodes duk amino acid da cewa wani bangare ne na enzyme. Regulation na enzymes iya faruwa a DNA matakin, idan samfur na dauki catalyzed isasshen gene kwafi Tashoshi da kuma akasin haka, idan akwai bukatar a samfurin, shi activates da kwafi tsari.

Da zarar mRNA aka saki a cikin cytoplasm, na gaba mataki - watsa shirye-shirye. A ribosomes endoplasmic reticulum hada farko sarkar kunshi amino acid nasaba da peptide bond. Duk da haka, da sunadarin a cikin primary tsari, zai iya ba tukuna yi ta enzymatic aiki.

A enzyme aiki shi ne dogara a kan furotin Tsarin. Same EPS gina jiki auku karkatarwa, game da shi kafa na farko na biyu da kuma sa'an nan manyan tsarin. Kira na wasu enzymes aka tsaya a wannan mataki, amma don bunkasa kuzari aiki ne sau da yawa dole abin da aka makala, kuma cofactor coenzyme.

A wasu wuraren da endoplasmic reticulum zo a haɗe kwayoyin gyara na enzyme: sugars, nucleic acid, fats da kuma bitamin. Wasu enzymes ba zai iya aiki ba tare da gaban da coenzyme.

Cofactor taka wata muhimmiyar rawa a cikin samuwar na quaternary tsarin da gina jiki. Wasu daga cikin ayyukan enzymes suna samuwa ne kawai a lokacin da furotin yankin kungiyar. Saboda haka yana da muhimmanci sosai ga kasancewarsu quaternary tsarin a cikin abin da wani a haɗa mahada tsakanin mahara da furotin da globules ne da karfe ion.

Mahara siffofin enzymes

Akwai yanayi a lokacin da ya zama dole gaban da dama enzymes cewa tsara guda dauki, amma bambanta da juna a cikin wasu madaidaci. Alal misali, enzyme iya aiki a 20 digiri, amma a 0 digiri, ya ba zai iya yi ta ayyuka. Abin da ya yi a cikin irin wannan halin da ake ciki, da mai rai jiki a low yanayin zafi?

Wannan matsala ne sauƙin warware ta gaban da dama enzymes cewa tsara guda dauki, amma a daban-daban aiki yanayin. Akwai iri biyu na mahara siffofin enzymes:

1. Isoenzymes. Irin wannan sunadarai na sauya ta daban-daban kwayoyin halittu, suna hada da daban-daban amino acid, amma tsara wannan dauki.
2. Gaskiya mahara siffofin. Wadannan sunadarai suna a rubuce daga wannan gene, amma ya auku a kan ribosomes gyara peptides. A fitarwa samar da dama siffofin guda enzyme.

A sakamakon haka, mahara siffofin na farko da irin da aka kafa a kayyade matakin, a lokacin da na biyu - a post-translational.

Ma'ana enzymes

A amfani da enzymes a magani zo saukar zuwa batu na sabon magunguna, a matsayin wani ɓangare na abin da abubuwa masu riga a dama yawa. Masana kimiyya sun ba tukuna sami hanyar rura kira na rasa enzymes a cikin jiki, amma yanzu ko'ina rarraba magunguna da cewa zai iya yin sama da lokacin da suka hasara.

Daban-daban enzymes a cell zuwa tsara manyan yawan halayen game da gyaran rayuwa. Daya daga cikin wadannan wakilan suna enizmov nucleases rukuni: endonuclease da exonuclease. Su aiki ne don kula da akai matakin na nucleic acid a cikin cell, kau na lalace DNA da RNA.

Kada ka manta game da sabon abu na jini clotting. Kamar yadda wani tasiri gwargwado na kariya, da tsari da aka sarrafawa da wani yawan enzymes. Cif daga gare su akwai thrombin, wanda sabobin tuba m gina jiki fibrinogen cikin fibrin aiki. Its thread Halicci irin cibiyar sadarwa da cewa occludes da jirgin ruwa rauni site, game da shi hana wuce kima jini hasãra.

Enzymes ake amfani a winemaking, zamanin] aular, samar da dama kiwo kayayyakin. Domin barasa daga glucose yisti za a iya amfani da shi, duk da haka, domin nasara da ya faru na wannan tsari da kuma cire isa da su.

Ban sha'awa facts game da wanda ba ku sani ba

- All na jiki ta enzymes da wata babbar salla - 5,000 zuwa 1,000,000 Da. Wannan shi ne saboda gaban furotin a cikin kwayoyin. Don kwatanta, kwayoyin nauyi na glucose - 180 Na'am, kuma carbon dioxide - a total na 44 a.

- Don kwanan wata, ya bude fiye da 2000 enzymes cewa an samu a cikin sel daban-daban kwayoyin. Duk da haka, mafi yawan wadannan abubuwa har yanzu ba cikakken gane.

- enzyme aiki da ake amfani domin samun tasiri wanka powders. A nan, enzymes cika wannan rawa kamar yadda a cikin jiki: suka rushe kwayoyin halitta, kuma wannan dukiya taimaka wajen fama aibobi. An shawarar yin amfani da irin wannan abu don wanka a zazzabi na ba fi 50 digiri, in ba haka ba shi yiwuwa zuwa denaturation tsari.

- Bisa kididdigar, 20% na duniya, mutane sha wahala daga rashin wani daga cikin enzymes.

- About da kaddarorin enzymes da aka sani na dogon lokaci, amma kawai a 1897, da mutane suka fahimci cewa ba da yisti, da kuma wani tsantsa daga Kwayoyin za a iya amfani da fermentation na sukari a cikin barasa.