Enzymes, raws li biocatalysts, zoo sib xws hauv ntau yam rau cov catalysts. Yog tias qhov ntau npaum li cas me me thiab cov catalytic efficiency siab. Zoo li cov catalysts dav dav, enzymes tsuas tuaj yeem hloov qhov ceev ntawm cov tshuaj tiv thaiv thiab tsis tuaj yeem hloov qhov sib npaug ntawm cov tshuaj tiv thaiv. Enzymes lawv tus kheej tsis hloov ua ntej thiab tom qab cov tshuaj tiv thaiv, yog li cov enzymes uas muaj cov ntsiab lus qis hauv cov hlwb tuaj yeem ua rau muaj kev hloov pauv ntau ntawm cov substrate hauv lub sijhawm luv luv, qhia txog kev ua haujlwm ntawm enzyme catalysis. Enzymes tuaj yeem txo qhov ua kom lub zog ntawm cov tshuaj tiv thaiv, tab sis tsis txhob hloov pauv lub zog dawb (△ G) thaum lub sij hawm cov txheej txheem tshuaj tiv thaiv, yog li ua kom cov tshuaj tiv thaiv ceev thiab txo lub sij hawm rau cov tshuaj tiv thaiv kom ncav cuag qhov sib npaug, tsis tas yuav hloov qhov sib npaug.
Cov nyhuv catalytic ntawm enzymes nthuav tawm cov yam ntxwv tshwj xeeb piv rau cov catalysts.
(A) kev ua haujlwm siab ntawm enzyme catalysis
Kev ua haujlwm catalytic ntawm enzyme yog ntau dua li cov tshuaj catalyst. Piv txwv li, catalase (muaj Fe2+) thiab inorganic hlau ions catalyze cov nram qab no decomposition cov tshuaj tiv thaiv ntawm hydrogen peroxide. 1 mol ntawm catalase tuaj yeem ua rau cov decomposition ntawm 5 × 106 mol ntawm H2O2 hauv 1 min. Nyob rau tib lub sijhawm, 1 mol ntawm cov tshuaj catalyst Fe2+ tsuas tuaj yeem ua rau 6 × 10-4 mol ntawm H2O2 decomposition. Piv nrog rau ob, lub catalytic efficiency ntawm catalase yog li ntawm 1010 npaug ntawm Fe2+.
Lub catalytic efficiency ntawm enzymes tuaj yeem qhia los ntawm lub tswv yim ntawm tus lej turnover. Tus lej hloov pauv yog hais txog tus lej ntawm cov molecules uas tuaj yeem hloov pauv los ntawm txhua lub enzyme molecule ib feeb twg thaum lub substrate concentration loj txaus, uas yog, tus naj npawb ntawm cov molecules uas catalyze cov tshuaj hloov pauv ntawm substrate. Raws li cov ntaub ntawv qhia saum toj no, tus lej hloov pauv ntawm catalase tuaj yeem suav ua 5 × 106. Tus lej hloov pauv ntawm cov enzymes feem ntau yog nyob ib ncig ntawm 1 000, thiab qhov loj tshaj plaws tuaj yeem ncav cuag ntau dua 106.
(B) qhov tshwj xeeb ntawm enzyme catalysis
Ib qho enzyme tsuas tuaj yeem ua rau qee chav kawm lossis ib yam khoom tshwj xeeb. Qhov no yog qhov tshwj xeeb ntawm kev ua enzyme. Piv txwv li, glycosidic bonds, ester bonds thiab peptide bonds tuaj yeem hydrolyzed los ntawm acid-base catalysis, tab sis cov enzymes uas hydrolyze cov tshuaj bonds sib txawv, xws li, cov sib txuas glycosidase, esterase thiab peptidase, uas yog, lawv tuaj yeem hydrolyzed los ntawm tshwj xeeb. enzymes feem.
(C) Cov tshuaj tiv thaiv kab mob catalyzed los ntawm enzyme yog me me.
Cov tshuaj tiv thaiv enzymatic feem ntau yuav tsum tau ua nyob rau hauv cov mob me me xws li qhov kub thiab txias, ib txwm muaj siab thiab nruab nrab pH tus nqi. Vim hais tias cov enzyme yog protein, nws yog ib qho yooj yim los poob nws cov kev ua ub no nyob rau hauv high kub, muaj zog acid, muaj zog alkali thiab lwm yam ib puag ncig. Vim hais tias cov enzyme yog rhiab heev rau kev hloov ntawm ib puag ncig sab nraud thiab yooj yim rau denature thiab inactivate, cov tshuaj tiv thaiv yuav tsum nruj me ntsis tswj thaum nws siv.
(D) kev hloov kho ntawm enzyme kev ua haujlwm
Piv nrog rau cov tshuaj catalysts, lwm qhov tshwj xeeb ntawm enzyme catalysis yog tias nws cov kev ua haujlwm catalytic tuaj yeem tswj tau. Txawm hais tias muaj ntau hom tshuaj tiv thaiv kab mob hauv cov kab mob, lawv muaj kev sib koom ua ke thiab sib koom ua ke. Kev hloov ntawm substrate concentration, cov khoom concentration thiab ib puag ncig tej yam kev mob tej zaum yuav cuam tshuam rau lub catalytic kev ua si ntawm lub enzyme, yog li tswj cov kev sib koom tes thiab kev loj hlob ntawm biochemical tshuaj. Kev tsis sib haum xeeb thiab kev tsis sib haum xeeb ntawm cov tshuaj tiv thaiv biochemical yuav ua rau muaj kab mob thiab kev tuag ntawm cov kab mob. Txhawm rau hloov mus rau ib puag ncig kev hloov pauv thiab tswj hwm kev ua neej nyob ib puag ncig, cov kab mob tau tsim cov txheej txheem ntawm kev tswj hwm kev ua haujlwm enzyme hauv cov txheej txheem evolution ntev. Muaj ntau txoj hauv kev los tswj cov enzymes, suav nrog kev tswj hwm inhibitor, kev tawm tswv yim cov cai, covalent hloov kho cov cai, kev ua kom zymogen thiab tswj cov tshuaj hormones.
(D) Kev ua haujlwm catalytic ntawm enzyme muaj feem xyuam rau coenzyme, pab pawg neeg thiab hlau ion.
Qee cov enzymes yog complex protein, nyob rau hauv uas me me molecules xws li coenzyme, cofactor thiab hlau ions yog ze ze rau lub catalytic kev ua si ntawm cov enzymes. Yog tias lawv raug tshem tawm, enzyme poob nws txoj haujlwm.
Cov ntaub ntawv hauv kab lus no yog los ntawm Is Taws Nem thiab tsis siv los ua cov lus qhia txog kev kho mob lossis cov lus qhia peev. Yog tias tsab xov xwm no muaj kev cuam tshuam rau koj txoj cai thiab kev txaus siab lossis xav paub txog cov khoom no, thov hu rau peb raws sijhawm kom peb tuaj yeem muab kev pab ntxiv rau koj