Proteases (proteinases, peptidases thiab proteolytic enzymes) ua lub luag haujlwm tseem ceeb hauv tib neeg lub neej. Txog niaj hnub no, ntau tshaj 500 ntawm cov enzymes no tau raug txheeb xyuas hauv tib neeg lub cev, uas yog encoded los ntawm 2% ntawm tag nrho cov noob. Kev ua haujlwm Proteolytic tau pom nyob rau hauv txhua hom kev ua neej thiab kab mob.
Kev faib tawm tseem ceeb
Raws li cov catalytic residue, proteases tuaj yeem muab faib ua 7 pawg dav:
- Serine - siv serine cawv.
- Cysteine - kev siv cysteine thiol.
- Threonine - hloov pauv ntawm cov cawv thib ob threonine.
- Aspartic - siv aspartate carboxylic acid.
- Glutamic - siv carboxylic acid glutamate.
- Metalloprotease - hlau tig, feem ntau zinc.
- Asparagine peptide lyases - Asparagine yog siv los ua cov tshuaj tiv thaiv kev cais tawm (tsis tas yuav dej).
Proteases thawj zaug tau muab faib ua 84 tsev neeg raws li lawv txoj haujlwm proteolytic, thiabcais raws li 4 hom catalytic:
- serine;
- cysteine;
- aspartic;
- metal.
Meaning
Tag nrho cov kev ua haujlwm proteolytic ua lub luag haujlwm tseem ceeb hauv ntau cov txheej txheem hauv lub cev. Cov no yog fertilization, digestion, loj hlob, maturation, laus thiab txawm tuag. Proteases tswj ntau cov txheej txheem physiological los ntawm kev tswj kev ua kom cov synthesis thiab deterioration ntawm cov zaub mov protein. Lawv ua lub luag haujlwm tseem ceeb hauv kev tsim thiab sib kis ntawm cov kab mob, cov kab mob thiab cov kab mob parasites thiab yog li lub luag haujlwm rau kev sib kis tau zoo ntawm cov kab mob tshwm sim los ntawm cov kab mob pathogenic. Cov enzymes no tso cai rau cov qog nqaij hlav sib faib, ua rau qhov chaw intercellular thiab cov hlab ntsha ntawm lub ntsws, thiab kis mus rau lwm cov ntaub so ntswg ntawm lub cev.
Biological functions
Proteolytic kev ua haujlwm muaj cov haujlwm hauv qab no:
- Post-translational processing. suav nrog kev tshem tawm methionine thiab/los yog hloov pauv ntawm cov protein tsis ua haujlwm lossis tsis ua haujlwm rau ib chav ua haujlwm.
- Cleavage ntawm precursor proteins. Qhov no yog qhov tsim nyog los xyuas kom meej tias cov protease tsuas yog qhib rau hauv qhov chaw raug thiab cov ntsiab lus. Kev ua tsis zoo proteolytic tuaj yeem ua rau lub cev puas tsuaj heev.
- Protein degradation. Tej zaum yuav tshwm sim intracellularly los yog extracellularly. Ua haujlwm ntau yam: tshem tawm cov protein uas puas thiab txawv txav; tiv thaiv lawv cov tsub zuj zuj; pab tswj cov txheej txheem cellular los ntawm kev tshem tawmenzymes.
- Kev zom zaub mov. Cov proteins uas tau los ntawm cov zaub mov tau tawg mus rau hauv peptide chains los ntawm pepsin, trypsin, chymotrypsin thiab elastase. Txhawm rau tiv thaiv tsis tsim nyog lossis ntxov ntxov ua kom lub plab zom mov (uas tuaj yeem ua rau mob pancreatitis), lawv ua raws li cov zymogen tsis ua haujlwm.
YEnzymes
Proteolytic enzymes muaj nyob rau hauv cov kab mob, kab mob, qee hom algae thiab nroj tsuag. Tab sis feem ntau ntawm lawv yog nyob rau hauv cov tsiaj. Muaj ntau hom kev ua haujlwm proteolytic ntawm enzymes. Lawv raug cais raws li qhov chaw nyob rau hauv qhov kev tawg ntawm cov proteins yog catalyzed. Ob pawg tseem ceeb yog exopeptides thiab endopeptidases. Hauv lub cev, cov khoom siv protein yog pib tawm tsam los ntawm pepsin. Thaum cov protein nkag mus rau hauv cov hnyuv me, nws yog ib feem ntawm lub plab zom mov. Ntawm no nws tau raug rau cov enzymes proteolytic secreted los ntawm pancreas. Tom qab ntawd pancreatic enzymes tau qhib rau hauv txoj hnyuv, hloov cov proteins rau hauv cov amino acids uas yooj yim nqus los ntawm nws cov phab ntsa. Yog li, tus txiav txiav tau tiv thaiv los ntawm kev zom nws tus kheej.
Bacteria
Microbial proteases yog ib pawg tseem ceeb hauv kev lag luam-kev lag luam tsim cov enzymes. Cov kev tshawb fawb tau ua los txiav txim siab txog kev ua haujlwm proteolytic ntawm cov kab mob txhawm rau txhawm rau txheeb xyuas lawv lub luag haujlwm hauv cov kab mob sib kis. Lub hom phiaj yog nyob rau hauv kev ntsuam xyuas cov kab mob lactic acid los ntawm ntau yam yogurts thiab fermented mis nyuj. Lawv yog dav faib nyob rau hauv cov xwm. Cov no yog lactobacilli, lactococci, bifidobacteria, streptococci, enterococci thiab sporolactobacilli. Lawv muab faib ua hom, subspecies, variants thiab hom.
Proteolytic kev ua haujlwm yog ib qho tseem ceeb ntawm cov kab mob lactic acid. Cov kab mob proteases yog cov enzymes uas catalyze hydrolysis peptide bonds hauv cov protein thiab polypeptides. Lawv ua lub luag haujlwm tseem ceeb hauv kev lag luam biotechnology thiab kws tshuaj. Cov kev tshawb fawb tau pom tias 13 hom kab mob muaj cov haujlwm proteolytic. Tsib ntawm lawv, xws li L1, L2, L6, L7, L9 pom qhov ua haujlwm siab tshaj plaws.
Peptins
Proteolytic kev ua ntawm pepsin yog ntsuas raws li kev cuam tshuam ntawm cov hlau nplaum ntawm lub cev. Cov qauv molecular ntawm pepsin yog tus cwj pwm los ntawm D-spatial symmetry. Lub inactive proenzyme pepsinogen yog synthesized nyob rau hauv lub hlwb ntawm lub plab mucosa. Nws kuj muaj nyob rau hauv ntau yam kua lom lom (ntshav, zis, seminal thiab cerebrospinal kua). Pepsinogen yog tus cwj pwm los ntawm kev ua kom autocatalytic. Nws secretion yog stimulated los ntawm vagus paj hlwb, sympathetic fibers, gastrin, histamine, secretin, thiab cholecystokinin. Gastrin ua raws li parietal cell stimulator. Qhov no polypeptide muaj nyob rau hauv 2 daim ntawv uas muaj 34 thiab 17 amino acids. Kev ntsuas ntawm cov kev ua haujlwm proteolytic ntawm pepsin cuam tshuam rau tus qauv hemoglobin tau qhia txog kev hloov pauv zoo sib xws hauv cov enzyme kev zom zaub mov.
Proteolysis thiab kab mob
Anomalous proteolytickev ua haujlwm yog txuam nrog ntau yam kab mob. Hauv cov kab mob pancreatitis, cov dej ntws tawm ntawm cov proteases thiab lawv qhov ua kom ntxov ntxov hauv cov txiav ua rau nws pib ua rau lub txiav ua haujlwm tsis zoo. Cov neeg mob ntshav qab zib tuaj yeem ua rau muaj kev ua haujlwm lysosome ntau ntxiv thiab kev degradation ntawm qee cov proteins tuaj yeem nce ntxiv. Cov kab mob inflammatory (rheumatoid mob caj dab) tuaj yeem ua rau tso tawm lysosomal enzymes mus rau hauv qhov chaw extracellular. Qhov no rhuav tshem cov ntaub so ntswg ib puag ncig. Qhov tsis sib xws ntawm cov proteases thiab cov tshuaj tiv thaiv tuaj yeem ua rau kev puas tsuaj ntawm lub ntsws cov ntaub so ntswg hauv emphysema tshwm sim los ntawm kev haus luam yeeb.
Lwm cov kab mob muaj xws li cov leeg nqaij dystrophy, tawv nqaij degeneration, kab mob ua pa thiab plab hnyuv, qog malignant.
Non-enzymatic proteolysis
Cov pob txha pob txha muaj protein ntau ruaj khov hauv dej ntawm nruab nrab pH thiab chav tsev kub, txawm hais tias tus nqi ntawm hydrolysis ntawm cov peptide sib txawv yuav txawv. Ib nrab-lub neej ntawm peptide daim ntawv cog lus decay yog li ntawm 7 mus rau 350 xyoo.
Cov ntxhia pob zeb muaj zog tuaj yeem yooj yim hydrolyze peptide bonds hauv cov proteins. Cov txheej txheem rau hydrolyse cov protein yog kom sov rau 105 ° C los yog tsau rau hauv hydrochloric acid rau 24 teev.
Kev txiav txim siab
Muaj ntau txoj hauv kev los txiav txim siab txog kev ua haujlwm proteolytic. Piv txwv li, hydrolysis ntawm casein, hemoglobin lossis azocasein. Thawj txoj kev tsis kim, tab sis casein nyuaj rau yaj. Txoj kev hemoglobin hydrolysis yog kim dua. Thaum siv nws, lub substrate yuav tsum tau denatured. Qhov thib peb txoj kev zam qhov no, tab sis nws kuj tsis pheej yig. Txoj kev ceev tshaj plaws, tsis kim yog kev siv mis nyuj substrate. Nws suav nrog cov cuab yeej siv tsawg dua thiab tuaj yeem siv rau hauv cov chav kawm. Txhua yam nws siv yog mis nyuj thiab da dej.
Kev sim ua txheej txheem
Ob milliliters ntawm cov tshuaj tsis haum (sodium acetate pH 5.0 uas muaj CaCI2) yog ntxiv rau 3 milliliters ntawm cov mis nyuj skimmed. Qhov sib tov no khaws cia ntawm 30 ° C hauv ib da dej rau 10 feeb. Txhawm rau pom cov txheej txheem mis coagulation, siv lub teeb ci. Nws hla mus rau ntau lub vib nas this raws li nws yuav siv sij hawm los coagulate ib daim ntawm cov mis nyuj qhov loj ntawm lub taub hau. Lub sijhawm txaus rau qhov raug yog nyob nruab nrab ntawm ib thiab ob feeb. Enzyme block yog txhais raws li qhov yuav tsum tau ua rau thawj coagulated fragment nyob rau hauv ib feeb nyob rau hauv cov kev xaiv ntawm kev sim.
Proteases as antiviral agents
Tam sim no, muaj ntau cov tshuaj pom zoo nrog cov haujlwm proteolytic siv rau kev kho tus kab mob kis. Feem ntau yog siv los kho tus kab mob herpesvirus, kab mob tib neeg tiv thaiv kab mob, kab mob ua pa syncytial, thiab kab mob khaub thuas A.
Kev tshawb fawb dhau kaum xyoo dhau los tau pom tias cov tshuaj tiv thaiv yog qhov yuav tsum tau muaj nyob hauv lub neej ntawm ntau tus kab mob. Influence tshwm sim ib yamlos ntawm cleavage ntawm siab molecular hnyav precursor proteins kom tau cov khoom ua haujlwm, los yog catalysis ntawm cov qauv proteins tsim nyog rau kev sib dhos thiab morphogenesis ntawm cov kab mob.
Txog hnub tim, plaub lub protease inhibitors tau pom zoo:
- "Saquinavir" (Invirase, Ro 31-8959).
- Indinavir (Crixivan, MK-639).
- "Ritonavir" (Norvir, AVT-538).
- "Nelfinavir" (Viracept, AG1343).
Lwm tshuaj
Picornavirus proteases yog ib tsev neeg loj tshaj plaws ntawm cov kab mob tseem ceeb ntawm tib neeg. Enteroviruses cuam tshuam nrog ntau yam kev kho mob, nrog rau cov kab mob ua pa sab saud, aseptic meningitis, encephalitis, myocarditis, tes, ko taw, thiab qhov ncauj kab mob. Hauv qhov no, proteases yuav pab tau. Expectorants nrog kev ua haujlwm proteolytic:
- "Trypsin".
- "Ribonuclease".
- "Chimozin"
Lwm yam tshuaj tiv thaiv kab mob rhinovirus yog Pleconaril.
