Qhov sib txawv tseem ceeb ntawm aspartyl cysteine thiab serine proteases yog lawv cov pab pawg ua haujlwm uas ua raws li catalytic residues. Cov pab pawg ua haujlwm uas ua raws li cov catalytic residues ntawm aspartyl protease yog ib pawg carboxylic acid, thaum nyob rau hauv cysteine protease, thiol los yog sulfhydryl pab pawg ua hauj lwm pab pawg neeg ntawm cov catalytic residue, thiab nyob rau hauv serine protease, ib pawg hydroxyl los yog cawv ua raws li pab pawg ua haujlwm ntawm catalytic residue.
Proteases yog cov enzymes uas ua rau cov tshuaj tiv thaiv proteolysis, uas yog kev tawg ntawm cov proteins rau hauv me me polypeptides lossis amino acids. Cov txheej txheem no tshwm sim los ntawm cleaving peptide bonds hauv cov proteins los ntawm cov txheej txheem hydrolysis. Proteases koom nrog ntau yam kev ua haujlwm lom neeg, xws li kev zom zaub mov ntawm cov protein uas tau noj, catabolism ntawm cov protein, thiab cov cim ntawm tes. Proteases muaj nyob rau hauv txhua yam ntawm lub neej. Aspartyl, cysteine, thiab serine yog peb qhov tseem ceeb proteases uas ua lub luag haujlwm tseem ceeb hauv cov kab mob nyob.
Aspartyl Proteases yog dab tsi?
Aspartyl proteases yog ib hom protein-breaking enzymes. Lawv muaj ob qho kev txuag aspartates hauv qhov chaw nquag, thiab lawv tau pom zoo ntawm acidic pH. Cov proteases cleave dipeptide bonds uas muaj hydrophobic residues nrog rau ib pawg beta-methylene. Lub catalytic mechanism ntawm aspartyl protease yog acid-puag mechanism. Qhov no suav nrog kev sib koom ua ke ntawm cov dej molecule nrog ob aspartate residues. Ib qho aspartate activates dej molecule los ntawm kev tshem tawm cov proton. Qhov no ua rau cov dej ua kom muaj kev tawm tsam nucleophilic ntawm carbonyl carbon ntawm substrate. Yog li ntawd, nws tsim ib qho tetrahedral oxyanion nruab nrab uas yog stabilized los ntawm hydrogen bonds nrog qhov thib ob aspartate residue. Kev hloov kho ntawm qhov nruab nrab no yog lub luag haujlwm rau kev sib cais ntawm peptide rau hauv ob qho khoom peptide.
Daim duab 01: Aspartyl Protease
Muaj tsib lub tsev neeg ntawm aspartic proteases: Clan AA uas yog tsev neeg, Clan AC, uas yog lub teeb liab peptidase II tsev neeg, Clan AD, uas yog tsev neeg presenilin, Clan AE, uas yog tsev neeg GPR endopeptidase, thiab Clan AF, uas yog tsev neeg omptin.
YCysteine Protease yog dab tsi?
Y Cysteine proteases yog ib pawg ntawm hydrolase enzymes uas degrade proteins. Lawv qhia cov txheej txheem catalytic uas cuam tshuam nrog nucleophilic cysteine thiol hauv catalytic triad lossis dyad. Thawj kauj ruam hauv catalytic mechanism ntawm cysteine proteases yog deprotonation. Cov pab pawg thiol dhau los ua deprotonated nyob rau hauv qhov chaw nquag ntawm cov enzyme los ntawm cov amino acid uas nyob ib sab xws li histidine, uas muaj cov saw hlau sab hauv. Cov kauj ruam tom ntej yog nucleophilic nres los ntawm deprotonated anionic sulfur ntawm cysteine ntawm lub substrate. Ntawm no, qhov tawg ntawm lub substrate tso tawm nrog ib qho amine, thiab cov histidine residue nyob rau hauv lub protease restores nws daim ntawv deprotonated. Qhov no tshwm sim hauv kev tsim cov thioester nruab nrab ntawm lub substrate, txuas cov carboxy terminus tshiab rau cysteine thiol. Lub thioester daim ntawv cog lus hydrolyzes los tsim carboxylic acid moiety ntawm cov seem substrate fragment.
Daim duab 02: Cysteine Protease
Cysteine proteases ua si ntau lub luag haujlwm hauv lub cev thiab kev loj hlob. Hauv cov nroj tsuag, lawv ua lub luag haujlwm tseem ceeb hauv kev loj hlob, kev loj hlob, tsub zuj zuj, thiab txhawb nqa cov protein cia. Nyob rau hauv tib neeg, lawv yog ib qho tseem ceeb nyob rau hauv senescence thiab apoptosis, lub cev tiv thaiv kab mob, prohormone processing, thiab extracellular matrix remodeling rau cone kev loj hlob.
Dab tsi yog Serine Proteases?
Serine proteases kuj yog ib pawg ntawm cov enzymes proteolytic uas tshem cov peptide bonds hauv cov protein. Serine ua haujlwm raws li nucleophilic amino acid ntawm qhov chaw ua haujlwm ntawm enzyme. Cov no muaj nyob rau hauv ob qho tib si eukaryotes thiab prokaryotes. Serine proteases feem ntau yog muab faib ua ntau pawg los ntawm cov qauv sib txawv uas muaj ob lub beta-chim sib txuas ntawm qhov chaw nquag catalytic thiab tseem ua raws li lawv cov substrate tshwj xeeb. Lawv zoo li trypsin, chymotrypsin-zoo li, thrombin-zoo li, elastase-zoo li, thiab subtilisin-zoo li.
Daim duab 03: Serine Protease
Trypsin-zoo li proteases cleave peptide daim ntawv cog lus tom qab cov amino acid zoo li lysine lossis arginine. Lawv yog cov tshwj xeeb rau cov khoom tsis zoo xws li aspartic acid lossis glutamic acid. Chymotrypsin-zoo li proteases yog ntau hydrophobic. Lawv qhov tshwj xeeb yog nyob nrog cov dej loj loj xws li tyrosine, tryptophan, thiab phenylalanine. Thrombin-zoo li proteases muaj xws li thrombin, uas yog cov ntaub so ntswg activating plasminogen, thiab plasmin. Cov no pab nyob rau hauv coagulation ntawm cov ntshav thiab digestion thiab kuj nyob rau hauv pathophysiology nyob rau hauv neurodegenerative teeb meem. Elastase zoo li proteases nyiam cov khoom seem xws li alanine, glycine, thiab valine. Subtilisin-zoo li proteases suav nrog serine hauv prokaryotes. Nws muab cov txheej txheem catalytic siv lub catalytic triad txhawm rau tsim cov nucleophilic serine. Kev tswj hwm ntawm serine protease kev ua si yuav tsum tau pib ua kom protease thiab tso tawm ntawm inhibitors.
Dab tsi yog qhov zoo sib xws ntawm Aspartyl Cysteine thiab Serine Proteases?
- Aspartyl, cysteine, thiab serine proteases catalyze cov proteins tawg los ntawm kev sib cais ntawm peptide bonds.
- Mechanisms zoo ib yam li qhov chaw ua haujlwm residues tawm tsam peptide bonds ua rau nws tawg.
- Txhua tus muaj nucleophiles.
- Lawv tag nrho yog cov proteins.
Qhov txawv ntawm Aspartyl Cysteine thiab Serine Proteases yog dab tsi?
Qhov sib txawv tseem ceeb ntawm aspartyl cysteine thiab serine proteases nyob ntawm lawv cov pab pawg ua haujlwm, uas ua raws li cov catalytic residues. Hauv aspartyl protease, pawg carboxylic acid ua raws li pab pawg ua haujlwm, thaum nyob hauv cysteine protease, thiol lossis sulfhydryl pawg ua haujlwm ua haujlwm, thiab hauv serine protease, pawg hydroxyl lossis cawv ua haujlwm ua haujlwm.
Aspartyl proteases muaj qhov chaw ua haujlwm aspartate, thaum cysteine proteases muaj cysteine active site. Lub active site residue ntawm serine protease yog ib pawg hydroxyl. Yog li, qhov no kuj yog lwm qhov sib txawv ntawm aspartyl cysteine thiab serine proteases. Tsis zoo li serine thiab cysteine proteases, aspartyl proteases tsis tsim covalent nruab nrab thaum tus txheej txheem ntawm cleaving. Yog li, proteolysis tshwm sim hauv ib kauj ruam rau aspartyl proteases.
Cov hauv qab no qhia txog qhov sib txawv ntawm aspartyl cysteine thiab serine proteases hauv daim ntawv tabular rau kev sib piv ntawm ib sab.
Summary – Aspartyl Cysteine vs Serine Proteases
Proteases yog cov enzymes uas ua kom cov proteins ua rau cov polypeptides me los yog amino acids. Qhov sib txawv tseem ceeb ntawm aspartyl cysteine thiab serine proteases yog cov pab pawg ua haujlwm uas ua raws li lawv cov catalytic residue. Ib pawg carboxylic acid ua raws li pab pawg ua haujlwm hauv aspartyl protease, thaum pawg thiol lossis sulfhydryl ua raws li pab pawg ua haujlwm hauv cysteine protease. Ib pawg hydroxyl lossis cawv ua haujlwm ua pawg hauv serine protease.
