Ib lub ntsiab lus ntawm lub neej yog raws li hauv qab no: "Lub neej yog ib txoj hauv kev uas muaj protein ntau lub cev." Nyob rau hauv peb lub ntiaj teb, tsis muaj kev zam, tag nrho cov kab mob muaj xws li cov organic raws li cov proteins. Kab lus no yuav piav qhia txog cov proteins yooj yim thiab nyuaj, txheeb xyuas qhov sib txawv ntawm cov qauv molecular, thiab tseem xav txog lawv txoj haujlwm hauv cell.
YYuav ua li cas yog proteins
Los ntawm qhov pom ntawm biochemistry, cov no yog cov organic polymers siab, cov monomers uas yog 20 hom amino acids sib txawv. Lawv sib cuam tshuam los ntawm covalent chemical bonds, txwv tsis pub hu ua peptide bonds. Txij li cov protein monomers yog cov tshuaj amphoteric, lawv muaj ob pawg amino thiab pawg carboxyl ua haujlwm. Ib daim ntawv cog lus tshuaj CO-NH tshwm sim ntawm lawv.
Yog tias polypeptide muaj cov amino acid residue, nws tsim cov protein yooj yim. Polymer molecules kuj muaj hlau ions, vitamins, nucleotides, carbohydrates yog complex proteins. Tom ntej no pebxav txog cov qauv spatial ntawm polypeptides.
Qib lub koom haum ntawm cov protein molecules
Lawv tuaj hauv plaub qhov kev teeb tsa sib txawv. Thawj cov qauv yog linear, nws yog qhov yooj yim tshaj plaws thiab muaj daim ntawv ntawm cov saw hlau polypeptide; thaum lub sij hawm nws spiralization, ntxiv hydrogen bonds yog tsim. Lawv stabilize lub helix, uas yog hu ua theem nrab qauv. Qib tertiary ntawm lub koom haum muaj cov proteins uas yooj yim thiab complex, feem ntau cov nroj tsuag thiab tsiaj hlwb. Qhov kawg configuration, lub quaternary, tshwm sim los ntawm kev sib cuam tshuam ntawm ob peb molecules ntawm lub haiv neeg qauv, sib sau ua ke los ntawm coenzymes, qhov no yog cov qauv ntawm complex proteins uas ua ntau yam functions nyob rau hauv lub cev.
Ntau hom proteins yooj yim
pawg no ntawm polypeptides tsis muaj ntau. Lawv cov molecules tsuas muaj cov amino acid residues. Proteins suav nrog, piv txwv li, histones thiab globulins. Thawj yog nthuav tawm hauv cov qauv ntawm cov nucleus thiab ua ke nrog DNA molecules. Cov pab pawg thib ob - globulins - suav tias yog cov khoom tseem ceeb ntawm cov ntshav plasma. Cov protein xws li gamma globulin ua haujlwm ntawm lub cev tiv thaiv kab mob thiab yog cov tshuaj tiv thaiv kab mob. Cov tebchaw no tuaj yeem tsim cov complex uas suav nrog cov carbohydrates thiab cov proteins. Fibrillar yooj yim cov proteins xws li collagen thiab elastin yog ib feem ntawm cov ntaub so ntswg, pob txha mos, tendons, thiab tawv nqaij. Lawv lub luag haujlwm tseem ceeb yog kev tsim kho thiab kev txhawb nqa.
Y Protein tubulin yog ib feem ntawm microtubules, uas yog cov khoom ntawm cilia thiab flagella ntawm cov kab mob unicellular xws li ciliates, euglena, parasitic flagellates. Tib cov protein muaj nyob rau hauv ntau cov kab mob (sperm flagella, qe cilia, ciliated epithelium ntawm txoj hnyuv me).
Albumin protein ua haujlwm cia (piv txwv li, qe dawb). Nyob rau hauv lub endosperm ntawm noob ntawm cereal nroj tsuag - rye, mov, nplej - protein molecules accumulates. Lawv hu ua cellular inclusions. Cov tshuaj no yog siv los ntawm cov noob kab mob thaum pib ntawm nws txoj kev loj hlob. Tsis tas li ntawd, cov ntsiab lus muaj protein ntau hauv cov nplej nplej yog ib qho tseem ceeb ntawm cov hmoov nplej zoo. Cov khob cij ci los ntawm cov hmoov nplej uas muaj gluten muaj qhov saj siab thiab noj qab nyob zoo. Gluten muaj nyob rau hauv lub npe hu ua durum nplej ntau yam. Cov ntshav plasma ntawm cov ntses tob hauv hiav txwv muaj cov protein uas tiv thaiv kom tsis txhob tuag los ntawm qhov txias. Lawv muaj antifreeze zog, tiv thaiv kev tuag ntawm lub cev ntawm cov dej kub. Ntawm qhov tod tes, cov phab ntsa ntawm tes ntawm cov kab mob thermophilic nyob hauv qhov chaw kub hnyiab muaj cov proteins uas tuaj yeem khaws lawv cov kev teeb tsa ntuj (tertiary lossis quaternary qauv) thiab tsis yog qhov kub ntawm +50 txog + 90 °С..
Proteids
Cov no yog cov proteins nyuaj, uas yog tus cwj pwm los ntawm ntau haiv neeg vim muaj cov haujlwm sib txawv uas lawv ua. Raws li tau sau tseg ua ntej, pawg no ntawm polypeptides, ntxiv rau cov protein, muaj cov pab pawg prosthetic. Raws li kev cuam tshuam ntawm ntau yam, xws li qhov kub thiab txias, ntsev ntawm cov hlau hnyav, concentrated alkalis thiab acids, cov protein ntau tuaj yeem hloov pauv lawv.spatial daim ntawv, simplifying nws. Qhov tshwm sim no hu ua denaturation. Cov qauv ntawm cov proteins complex yog tawg, hydrogen bonds tawg, thiab molecules poob lawv cov khoom thiab kev ua haujlwm. Raws li txoj cai, denaturation yog irreversible. Tab sis rau qee cov polypeptides uas ua cov catalytic, lub cev muaj zog thiab cov teeb liab ua haujlwm, renaturation yog ua tau - rov qab kho cov qauv ntawm cov protein.
Yog tias qhov kev txiav txim ntawm qhov tsis txaus ntseeg tshwm sim rau lub sijhawm ntev, cov protein molecule raug rhuav tshem tag nrho. Qhov no ua rau cleavage ntawm peptide bonds ntawm lub hauv paus qauv. Nws tsis tuaj yeem rov qab kho cov protein thiab nws cov haujlwm. Qhov tshwm sim no hu ua kev puas tsuaj. Ib qho piv txwv yog qhov kub ntawm cov qe qaib: kua protein - albumin, uas yog nyob rau hauv lub tertiary qauv, puas tag.
YProtein biosynthesis
Nco ntsoov ib zaug ntxiv tias cov muaj pes tsawg leeg ntawm polypeptides ntawm cov kab mob muaj sia suav nrog 20 amino acids, ntawm cov uas muaj qhov tseem ceeb. Cov no yog lysine, methionine, phenylalanine, thiab lwm yam. Lawv nkag mus rau hauv cov hlab ntsha los ntawm cov hnyuv me tom qab kev puas tsuaj ntawm cov khoom protein nyob hauv nws. Txhawm rau tsim cov amino acids uas tsis tseem ceeb (alanine, proline, serine), fungi thiab tsiaj txhu siv cov tshuaj muaj nitrogen. Cov nroj tsuag, ua autotrophs, nws tus kheej tsim tag nrho cov tsim nyog compound monomers, sawv cev rau cov proteins nyuaj. Txhawm rau ua qhov no, lawv siv nitrates, ammonia lossis nitrogen dawb hauv lawv cov tshuaj tiv thaiv assimilation. Hauv cov kab mob, qee hom muab lawv tus kheej nrog cov txheej txheem ntawm cov amino acids tag nrho, thaum lwm tus tsuas yog qee cov monomers tau tsim. Cov theemprotein biosynthesis tshwm sim nyob rau hauv lub hlwb ntawm tag nrho cov muaj sia nyob. Transcription tshwm sim nyob rau hauv lub nucleus, thiab kev txhais lus tshwm sim nyob rau hauv lub cytoplasm ntawm lub cell.
Thawj theem - kev sib txuas ntawm mRNA precursor tshwm sim nrog kev koom tes ntawm enzyme RNA polymerase. Nws tawg hydrogen bonds ntawm DNA strands, thiab ntawm ib tug ntawm lawv, raws li lub hauv paus ntsiab lus ntawm complementarity, nws assembles ib tug pre-mRNA molecule. Nws dhau mus hlais, uas yog, nws loj tuaj, thiab tom qab ntawd tawm ntawm cov nucleus mus rau hauv cytoplasm, tsim cov matrix ribonucleic acid.
Rau qhov kev siv ntawm theem ob, nws yog ib qho tsim nyog yuav tsum muaj cov organelles tshwj xeeb - ribosomes, nrog rau cov khoom siv ntawm cov ntaub ntawv thiab thauj ribonucleic acids. Lwm qhov xwm txheej tseem ceeb yog qhov muaj ATP molecules, txij li cov kev hloov pauv ntawm cov yas, uas suav nrog cov protein biosynthesis, tshwm sim nrog lub zog nqus.
Enzymes, lawv cov qauv thiab kev ua haujlwm
Qhov no yog ib pawg loj ntawm cov proteins (kwv yees li 2000) uas ua raws li cov tshuaj uas cuam tshuam rau tus nqi ntawm cov tshuaj biochemical hauv cov hlwb. Lawv tuaj yeem ua tau yooj yim (trepsin, pepsin) lossis complex. Cov proteins nyuaj muaj xws li coenzyme thiab apoenzyme. Qhov tshwj xeeb ntawm cov protein nws tus kheej nrog kev hwm rau cov tebchaw uas nws ua rau txiav txim siab cov coenzyme, thiab cov haujlwm ntawm cov protein tau pom tsuas yog thaum cov protein tivthaiv cuam tshuam nrog apoenzyme. Kev ua haujlwm catalytic ntawm ib qho enzyme tsis nyob ntawm tag nrho cov molecule, tab sis tsuas yog nyob rau ntawm qhov chaw nquag. Nws cov qauv sib raug rau cov qauv tshuaj ntawm cov tshuaj catalyzed raws li txoj cai"key-lock", yog li qhov kev txiav txim ntawm enzymes yog nruj me ntsis txwv. Cov haujlwm ntawm cov proteins nyuaj yog ob qho tib si kev koom tes hauv cov txheej txheem metabolic thiab lawv siv raws li kev lees paub.
chav kawm ntawm cov proteins complex
Lawv tau tsim los ntawm biochemists raws li 3 yam: lub cev thiab tshuaj lom neeg, kev ua haujlwm zoo thiab cov yam ntxwv tshwj xeeb ntawm cov protein. Thawj pab pawg muaj xws li polypeptides uas txawv hauv electrochemical zog. Lawv muab faib ua tej yam yooj yim, nruab nrab thiab acidic. Nrog rau dej, cov proteins tuaj yeem yog hydrophilic, amphiphilic thiab hydrophobic. Cov pab pawg thib ob suav nrog cov enzymes, uas tau txiav txim siab los ntawm peb ua ntej. Cov pab pawg thib peb suav nrog polypeptides uas sib txawv hauv cov tshuaj muaj pes tsawg leeg ntawm pawg prosthetic (cov no yog chromoproteins, nucleoproteins, metalloproteins).
Cia peb xav txog cov khoom ntawm cov proteins nyuaj kom ntxaws ntxiv. Piv txwv li, ib qho acidic protein uas yog ib feem ntawm ribosomes muaj 120 amino acids thiab yog universal. Nws muaj nyob rau hauv cov protein-synthesizing organelles ntawm ob leeg prokaryotic thiab eukaryotic hlwb. Lwm tus neeg sawv cev ntawm pab pawg no, S-100 protein, muaj ob txoj hlua txuas los ntawm calcium ion. Nws yog ib feem ntawm cov neurons thiab neuroglia - cov ntaub so ntswg ntawm lub paj hlwb. Ib qho cuab yeej cuab tam ntawm tag nrho cov acidic proteins yog cov ntsiab lus siab ntawm dibasic carboxylic acids: glutamic thiab aspartic. Alkaline proteins suav nrog histones - cov proteins uas yog ib feem ntawm nucleic acids ntawm DNA thiab RNA. Ib tug feature ntawm lawv cov tshuaj muaj pes tsawg leeg yog ib tug loj npaum li cas ntawm lysine thiab arginine. Histones, ua ke nrog cov chromatin ntawm cov nucleus, tsim chromosomes - cov qauv tseem ceeb tshaj plaws ntawm cov kab mob ntawm tes. Cov proteins no koom nrog hauv cov txheej txheem ntawm kev sau thiab txhais lus. Amphiphilic proteins yog dav nyob rau hauv cell membranes, tsim ib tug lipoprotein bilayer. Yog li, tau kawm txog cov pab pawg ntawm cov proteins nyuaj uas tau hais los saum no, peb tau ntseeg tias lawv cov khoom siv physicochemical yog txiav txim siab los ntawm cov qauv ntawm cov protein tivthaiv thiab cov pab pawg prosthetic.
Qee lub cell membrane cov proteins muaj peev xwm paub txog thiab teb rau ntau yam tshuaj lom neeg, xws li antigens. Qhov no yog lub cim qhia txog kev ua haujlwm ntawm cov protein, nws yog ib qho tseem ceeb heev rau cov txheej txheem ntawm kev xaiv nqus cov khoom los ntawm ib puag ncig sab nraud thiab rau kev tiv thaiv.
YGlycoproteins thiab proteoglycans
Lawv yog cov proteins nyuaj uas sib txawv ntawm ib leeg hauv biochemical muaj pes tsawg leeg ntawm pawg prosthetic. Yog tias cov tshuaj sib txuas ntawm cov protein thiab cov carbohydrate yog covalent-glycosidic, cov tshuaj no hu ua glycoproteins. Lawv apoenzyme yog sawv cev los ntawm cov molecules ntawm mono- thiab oligosaccharides, piv txwv ntawm cov proteins xws li prothrombin, fibrinogen (cov protein koom nrog hauv cov ntshav coagulation). Cortico- thiab gonadotropic cov tshuaj hormones, interferons, membrane enzymes kuj yog glycoproteins. Nyob rau hauv proteoglycan molecules, cov protein ib feem tsuas yog 5%, tus so ntog rau ntawm prosthetic pawg (heteropolysaccharide). Ob qho tib si txuas nrog glycosidic daim ntawv cog lus ntawm OH-threonine thiab arginine pawg thiab NH₂-glutamine thiab lysine pawg. Proteoglycan molecules ua lub luag haujlwm tseem ceeb hauv cov dej- ntsev metabolism ntawm cov cell. Hauv qab nonthuav qhia ib lub rooj ntawm cov proteins uas tau kawm los ntawm peb.
| Cov khoom tsim ntawm cov pab pawg prosthetic | |
| 1. Monosaccharides (qabzib, galactose, mannose) | 1. Hyaluronic Acid |
| 2. Oligosaccharides (m altose, lactose, sucrose) | 2. Chondroitic acid. |
| 3. Acetylated amino derivatives ntawm monosaccharides | 3. Heparin |
| 4. Deoxysaccharides | |
| 5. Neuramic thiab sialic acids | |
Metalloproteins
Cov tshuaj no muaj ions ntawm ib lossis ntau cov hlau hauv lawv cov molecules. Xav txog cov piv txwv ntawm complex proteins teej tug mus rau pawg saum toj no. Cov no feem ntau yog cov enzymes xws li cytochrome oxidase. Nws yog nyob rau ntawm cristae ntawm mitochondria thiab activates ATP synthesis. Ferrin thiab transferrin yog cov proteins uas muaj hlau ions. Thawj deposits lawv nyob rau hauv lub hlwb, thiab lub thib ob yog ib tug thauj protein nyob rau hauv cov ntshav. Lwm cov metalloprotein yog alpha-amelase, nws muaj calcium ions, yog ib feem ntawm cov qaub ncaug thiab kua txiv pancreatic, koom nrog hauv kev ua kom cov hmoov txhuv nplej siab. Hemoglobin yog ob qho tib si metalloprotein thiab chromoprotein. Nws ua haujlwm ntawm kev thauj cov protein, nqa oxygen. Yog li ntawd, lub compound oxyhemoglobin yog tsim. Thaum cov pa roj carbon monoxide, txwv tsis pub hu ua carbon monoxide, yog nqus tau, nws cov molecules tsim ib qho chaw ruaj khov nrog erythrocyte hemoglobin. Nws kis tau sai sai los ntawm cov kabmob thiab cov ntaub so ntswg, ua rau muaj tshuaj lom.hlwb. Yog li ntawd, nrog kev nqus pa ntev ntev ntawm cov pa roj carbon monoxide, kev tuag tshwm sim los ntawm kev ua tsis taus pa. Hemoglobin kuj tseem hloov pauv cov pa roj carbon dioxide tsim hauv cov txheej txheem catabolism. Nrog rau cov ntshav ntws, carbon dioxide nkag mus rau hauv lub ntsws thiab lub raum, thiab los ntawm lawv - mus rau hauv ib puag ncig sab nraud. Hauv qee cov crustaceans thiab molluscs, hemocyanin yog cov protein nqa oxygen. Hloov cov hlau, nws muaj tooj liab ions, yog li cov ntshav ntawm cov tsiaj tsis liab, tab sis xiav.
Chlorophyll Functions
Raws li peb tau hais ua ntej lawm, cov proteins nyuaj tuaj yeem tsim cov complexes nrog cov xim - xim xim organic. Lawv cov xim nyob ntawm cov chromoform pawg uas xaiv tau nqus qee yam ntawm lub hnub ci. Hauv cov nroj tsuag muaj cov plastids ntsuab - chloroplasts muaj cov xim chlorophyll. Nws muaj magnesium atoms thiab polyhydric cawv phytol. Lawv koom nrog cov protein molecules, thiab cov chloroplasts lawv tus kheej muaj thylakoids (phaj), los yog daim nyias nyias txuas hauv pawg - grana. Lawv muaj cov xim photosynthetic - chlorophylls - thiab ntxiv carotenoids. Ntawm no yog tag nrho cov enzymes siv nyob rau hauv photosynthetic tshuaj. Yog li, chromoproteins, uas suav nrog chlorophyll, ua lub luag haujlwm tseem ceeb tshaj plaws hauv cov metabolism, uas yog nyob rau hauv kev cuam tshuam ntawm assimilation thiab dissimilation.
YViral proteins
Lawv tau khaws cia los ntawm cov neeg sawv cev ntawm cov ntawv tsis yog cellular uas yog ib feem ntawm Vira Realm. Cov kab mob tsis muaj lawv tus kheej cov khoom siv protein-synthesizing. Nucleic acids, DNA lossis RNA, tuaj yeem ua rau kev sib txuasnws tus kheej hais los ntawm lub cell nws tus kheej kis tus kab mob. Cov kab mob yooj yim tsuas yog muaj cov protein molecules sib sau ua ke rau hauv cov qauv helical lossis polyhedral, xws li cov kab mob luam yeeb mosaic. Cov kab mob nyuaj muaj ib daim nyias nyias ntxiv uas tsim ib feem ntawm cov plasma membrane ntawm tus tswv tsev cell. Nws tuaj yeem suav nrog glycoproteins (tus kab mob siab B, kab mob khaub thuas). Lub luag haujlwm tseem ceeb ntawm glycoproteins yog kev lees paub ntawm cov receptors tshwj xeeb ntawm cov cell membrane. Cov hnab ntawv kab mob ntxiv kuj suav nrog cov enzymes proteins uas ua kom DNA rov ua dua lossis RNA hloov pauv. Raws li cov lus hais saum toj no, cov lus xaus hauv qab no tuaj yeem kos tau: lub hnab ntawv cov proteins ntawm cov kab mob sib kis muaj cov qauv tshwj xeeb uas nyob ntawm daim nyias nyias ntawm cov cell cell.
Nyob rau hauv tsab xov xwm no, peb muaj cov yam ntxwv ntawm cov proteins nyuaj, kawm txog lawv cov qauv thiab kev ua haujlwm hauv cov hlwb ntawm ntau yam kab mob.
