Cov tseem ntawm lub enzyme: hom thiab cov yam ntxwv ntawm cov kev txiav txim

Lo lus "enzyme" muaj Latin. Txhais nws txhais tau tias "leaven". Cov kawm lus Askiv siv lub sij hawm "enzyme", derived ntawm cov Greek lub sij hawm lub ntsiab lus tib yam nkaus li. Enzymes hu ua tshwj xeeb proteins. Lawv tsim nyob rau hauv lub hlwb thiab muaj lub peev xwm rau accelerate lub chav kawm ntawm biochemical dab. Nyob rau hauv lwm yam lus, lawv ua raws li lom catalysts. Xav txog ntxiv tias nruab nrab yog ib tug tseem ntawm enzymes. также будут описаны в статье. Hom tseem yuav tau piav nyob rau hauv tsab xov xwm.

General yam ntxwv

Lub manifestation ntawm lub catalytic kev ua ntawm ib co enzymes yog tshwm sim los ntawm lub xub ntiag ntawm ib tug xov tooj ntawm cov tebchaw uas tsis yog-protein xwm. Lawv yog cov hu ua cofactors. Lawv muab faib ua ob pawg: hlau ions, thiab ib tug xov tooj ntawm inorganic tshuaj raws li zoo raws li coenzymes (organic tebchaw).

kev ua si mechanism

Los ntawm lawv tshuaj xwm, enzymes yog ib pab pawg neeg ntawm proteins. Txawm li cas los, tsis zoo li yav tas, lub ntsiab nyob rau hauv lo lus nug muaj cov active site. Nws yog ib tug cim txheej ntawm functional pawg ntawm cov amino acid residues. Lawv nruj me ntsis taw qhia kom paub nyob rau hauv qhov chaw vim lub tertiary los yog quaternary qauv ntawm cov enzyme. Nyob rau hauv lub active site ntawm lub catalyst thiab substrate tso tawm qhov chaw. Xeem - yog dab tsi yog vim lub tseem ntawm enzymes. Lub substrate yog lub tshuaj uas ua rau lub protein. Yav tas los nws twb xav hais tias lawv sib tham yog nqa tawm nyob rau hauv ib tug "xauv thiab qhov tseem ceeb". Nyob rau hauv lwm yam lus, lub active site yuav tsum zoo phim lub substrate. Tam sim no yeej los ntawm ib tug txawv hypothesis. Nws yog xav hais tias chiv muaj yog tsis muaj caij nyoog match, tab sis nws zoo nkaus li nyob rau hauv lub chav kawm ntawm lub sis ntawm tshuaj. Qhov thib ob - ib tug catalyst - ib qhov chaw muaj feem xyuam rau cov tseem ntawm kev txiav txim. Nyob rau hauv lwm yam lus, nws txhais lub ntsiab ntawm qhov ceev cov tshuaj tiv thaiv.

qauv

Tag nrho cov enzymes raug muab faib ua ib thiab ob-tivthaiv. Cov yav tas los muaj ib tug qauv zoo li tus qauv yooj yim proteins. Lawv muaj tsuas yog tus amino acids. Ob txhais pab pawg neeg - proteid - muaj xws li cov protein ntau thiab uas tsis yog-protein feem. Xeem ua Coenzyme thawj - apoenzyme. Xeem txiav txim seb tus substrate tseem ntawm lub enzyme. Hais tias yog, nws ua rau cov kev ua ntawm lub substrate seem nyob rau hauv lub active site. Coenzyme, ntsig txog, ua hauj lwm pab raws li ib tug catalytic cheeb tsam. Nws yuav lub tseem ntawm kev txiav txim. Raws li tau ua raws li coenzymes vitamins, co, thiab lwm yam tsawg molecular yuag tebchaw.

catalysis

Tshwm sim ntawm tej tshuaj cov tshuaj tiv thaiv vim lub sib tsoo ntawm molecules interacting tshuaj. Lawv lub zog nyob rau hauv lub system yog txiav txim los ntawm lub xub ntiag ntawm tej zaum free zog. Tshuaj lom neeg tshua yuav tsum molecules coj lub xeev txoj kev hloov. Nyob rau hauv lwm yam lus, lawv yuav tsum muaj hwj huam txaus rau dua ib tug zog barrier. Nws nruab nrab yog qhov tsawg kawg nkaus tus nqi ntawm lub zog rau impart tag nrho cov molecules reactivity. Tag nrho cov catalysts, enzymes xws li, tau txo lub zog barrier. Qhov no muaj txhawb rau ceev kev kawm ntawm cov tshuaj tiv thaiv.

Nyob rau hauv dab tsi tshwm tseem ntawm enzymes?

Qhov no muaj peev xwm yog reflected nyob rau hauv lub acceleration ntawm xwb ib lub tshuaj tiv thaiv. Enzymes yuav cuam tshuam ib tug thiab tib substrate. Txawm li cas los, lawv txhua tus yuav tsuas leeb cov kev tshuaj tiv thaiv. Cov tshuaj tiv thaiv tseem ntawm lub enzyme yuav pom nyob rau hauv lub pyruvate dehydrogenase complex. Nws muaj cov nqaijrog, rau lub PVC. Lub ntsiab yog: pyruvate dehydrogenase, pyruvate decarboxylase, acetyl. Cov tshuaj tiv thaiv nws tus kheej yog raug xa mus rau raws li oxidative decarboxylation ntawm STC. Cov khoom ua raws li nws cov acetic acid kom nquag plias.

kev faib

Cov nram qab no hom ntawm kev enzymes:

1. Stereochemistry. Nws yog qhia nyob rau hauv lub peev xwm ntawm ib yam khoom uas muaj kev cuam tshuam ib tug ntawm cov tau stereoisomers ntawm lub substrate. Piv txwv li, nws muaj peev xwm sawv ntawm sawv fumaratgidrotaza fumarate. Txawm li cas los, nws tsis cuam tshuam rau cis-isomer - maleic acid.
2. Tsis. этого типа выражается в способности вещества влиять только на конкретный субстрат. Cov tseem ntawm lub enzyme ntawm no hom yog qhia nyob rau hauv lub peev xwm ntawm ib yam khoom uas muaj kev cuam tshuam tsuas ib lub substrate. Piv txwv li, sucrase reacts tsuas nrog sucrose, arginase - arginine thiab thiaj li nyob.
3. Tus kwv tij. в этом случае выражена в способности вещества влиять на группу субстратов, имеющих связь одинакового типа. Cov tseem ntawm lub enzyme nyob rau hauv cov ntaub ntawv no yog hais nyob rau hauv lub peev xwm ntawm ib yam khoom uas muaj kev cuam tshuam ib pab pawg neeg ntawm substrates muaj ib tug daim ntawv cog lus ntawm tib hom. Piv txwv li, alpha-amylase reacts nrog glycogen thiab cov hmoov txhuv nplej. Lawv muaj ib tug kev twb kev txuas glycoside hom. Trypsin, pepsin, chymotrypsin cuam tshuam ntau cov nqaijrog peptide pab pawg neeg.

kub

в определенных условиях. Enzymes yog hais nyob rau hauv tej yam tej yam kev mob. Rau feem ntau ntawm lawv raws li qhov zoo tshaj plaws coj qhov kub ntawm + 35 ... + 45 degrees. Thaum ib tse nrog koj tshuaj nyob rau hauv cov nqe lus ntawm nqi qis, txoj kev yuav txo. Qhov no mob yog raug xa mus rau raws li ib tug reversible inactivation. Thaum nws kub ntawm lub nce muaj peev xwm rov qab los. Nws yog tau hais tias thaum muab tso nyob rau tej yam kev mob, qhov chaw uas t yog lub saum toj no qhov tseem ceeb kuj tshwm sim inactivation. Txawm li cas los, nyob rau hauv cov ntaub ntawv no nws yuav tsum irreversible, raws li yog rov qab los los ntawm tej lub kub. Qhov no yog vim lub denaturation ntawm cov qauv.

Nyhuv ntawm pH

Lub acidity ntawm tus nqi ntawm lub molecule nyob. Raws li, qhov pH influences cov kev ua thiab tseem ntawm lub active site ntawm lub enzyme. Optimum acidity index rau txhua yam khoom uas ib tug. Txawm li cas los, nyob rau hauv Feem ntau nws yog 4-7. Piv txwv li, rau ib tug alpha-amylase ntawm cov qaub ncaug zoo acidity yog 6.8. Meanwhile, muaj ib tug xov tooj ntawm kev zam. Lub optimum acidity pepsin, piv txwv li, 1.5-2.0, chymotrypsin thiab trypsin - 8-9.

concentration

Qhov ntau enzyme yog tam sim no, ntau dua qhov lub tshuaj tiv thaiv tus nqi. Ib tug zoo xws li cov xaus yuav ua tau twv nrog kev sib hwm mus rau lub substrate concentration. Txawm li cas los, raws txiav txim rau txhua tus tshuaj ib saturating lub hom phiaj ntsiab lus. Thaum nws tag nrho cov active chaw nyob los ntawm cov uas twb muaj lawm substrate. будет максимальной, вне зависимости от последующего добавления мишеней. Yog li cov tseem ntawm lub enzyme yog ib tug tshaj plaws, tsis hais ntawm lub tom ntej tsis tas li ntawd ntawm lub hom phaj.

Substance-regulators

Lawv yuav tsum tau muab faib mus rau hauv inhibitors thiab activators. Ob leeg ntawm cov pawg no faib mus rau hauv nonspecific thiab meej. Rau lub caij nyoog kawg no hom xws li avtivatoram zhelchnokislye ntsev (rau lipase podzheluzhochnoy caj pas), tshuaj chlorine ua ions (alpha-amylase), hydrochloric acid (rau pepsin). Nonspecific activators yog magnesium ions uas muaj feem xyuam kinases thiab phosphatases, thiab tej inhibitors - davhlau ya nyob twg peptides proenzymes. Cov yav tas yog tsaug zog ntaub ntawv ntawm cov tshuaj. Lawv tshuab txais los ntawm cleavage ntawm davhlau ya nyob twg peptides. Lawv sib haum mus rau tej hom ntawm txhua tus neeg proenzyme. Piv txwv li, nyob rau hauv ib tug tsaug zog hauv daim ntawv ntawm trypsin ua nyob rau hauv daim ntawv ntawm cov trypsinogen. Nws active chaw kaw davhlau ya nyob twg hexapeptide, uas yog ib txog kev inhibitor. Qhov ua kom tus txheej txheem yog nws cleavage. Lub active site ntawm trypsin raws li ib tug tshwm sim ntawm no, nws yuav qhib. Nonspecific inhibitors yog ntsev ntawm hnyav hlau. Piv txwv li, tooj liab sulfate. Lawv ua denaturation ntawm tebchaw.

inhibition

Nws yuav ua tau kev sib tw. Qhov no tshwm sim yog hais nyob rau hauv qhov tshwm sim ntawm cov yam ntxwv zoo sib thooj ntawm cov inhibitor thiab lub substrate. Lawv koom nyob rau hauv ib tug tawm tsam rau lub link mus rau lub active site. Yog hais tias lub inhibitor cov ntsiab lus yog siab tshaj lub substrate yog tsim kopleksferment inhibitor. Thaum muab cov phiaj tshuaj piv hloov. Raws li ib tug tshwm sim, lub inhibitor yuav tau los hloov. Piv txwv li, lub succinate rau succinate dehydrogenase ua raws li ib tug substrate. Contact lenses yog oxaloacetate los yog malonate. Sib tw khoom uas xam tau tias yog mus cuam tshuam cov tshuaj tiv thaiv. Feem ntau, lawv yuav zoo ib substrates. Piv txwv li, rau piam thaj 6-phosphate cov khoom no yog qabzib. Lub substrate yuav tsum yog tib yam glucose-6 phosphate. Noncompetitive inhibition yog tsis npaj rau cov yam ntxwv zoo sib thooj ntawm cov tshuaj. Inhibitor thiab substrate yuav ib txhij khi rau cov enzyme. Yog li muaj yog tsim ntawm ib tug tshiab compound. Lawv yog kompleksferment-substrate inhibitor. Thaum lub sij hawm tus sis ntawm cov active center lawm. Qhov no yog vim lub losis tswvyim dabtsi nrog cov catalytic site inhibitor ntawm lub active site. Ib qho piv txwv yog lub cytochrome oxidase. Rau no enzyme ua hauj lwm pab raws li ib tug substrate oxygen. Cytochrome oxidase inhibitors yog ntsev ntawm hydrocyanic acid.

allosteric kev cai

Nyob rau hauv tej rooj plaub, tshwj tsis yog lub active chaw, uas txiav txim seb tus tseem ntawm lub enzyme, muaj lwm link. Lub tivthaiv ua raws li ib tug allosteric nws. Yog hais tias lub tib lub npe yog txuam nrog nws ib tug activator ntawm lub enzyme tsub kom cov hauj lwm zoo. Yog hais tias nyob rau hauv teb mus rau lub allosteric inhibitor nkag mus rau hauv qhov chaw, lub active tshuaj, ntsig txog, txo. Piv txwv li, adenylate cyclase thiab guanylate cyclase hais txog ib qho enzyme nrog allosteric kev cai hom.