Kev hloov pauv ntawm cov amino acids yog cov txheej txheem ntawm kev hloov pauv hloov pauv los ntawm cov khoom pib ntawm cov amino pawg mus rau keto acid yam tsis muaj kev tsim ntawm ammonia. Cia peb xav paub ntau ntxiv txog cov yam ntxwv ntawm cov tshuaj tiv thaiv no, nrog rau nws lub ntsiab lus lom neeg.
Discovery keeb kwm
Cov tshuaj amino acid transamination tau tshawb pom los ntawm Soviet chemists Kritzman thiab Brainstein xyoo 1927. Cov kws tshawb fawb tau ua haujlwm ntawm cov txheej txheem ntawm deamination ntawm glutamic acid hauv cov leeg nqaij thiab pom tias yog pyruvic thiab glutamic acids ntxiv rau homogenate ntawm cov leeg nqaij, alanine thiab α-ketoglutaric acid yog tsim. Qhov tshwj xeeb ntawm qhov kev tshawb pom yog tias cov txheej txheem tsis tau nrog kev tsim ntawm ammonia. Thaum lub sijhawm sim, lawv tau tswj xyuas kom pom tias kev hloov pauv ntawm cov amino acids yog cov txheej txheem thim rov qab.
Thaum qhov kev tshwm sim tshwm sim, cov enzymes tshwj xeeb tau siv los ua cov catalysts, uas yog hu ua aminoferases (transmaminases).
txheej txheem nta
Amino acids koom nrog hauv kev hloov pauv tuaj yeem yog cov tshuaj monocarboxylic. Hauv kev tshawb fawb hauv chav kuaj, nws tau pom tias transaminationasparagine thiab glutamine nrog keto acids tshwm sim hauv cov ntaub so ntswg tsiaj.
Kev koom tes hauv kev hloov pauv ntawm pawg amino siv pyridoxal phosphate, uas yog coenzyme ntawm transaminases. Hauv cov txheej txheem ntawm kev sib cuam tshuam, pyridoxamine phosphate yog tsim los ntawm nws. Enzymes ua lub luag haujlwm rau cov txheej txheem no: oxidase, pyridoxaminase.
Reaction mechanism
Kev hloov pauv ntawm cov amino acids tau piav qhia los ntawm cov kws tshawb fawb Soviet Shemyakin thiab Braunstein. Tag nrho cov transaminases muaj cov coenzyme pyridoxal phosphate. Cov tshuaj tiv thaiv kev sib kis nws nrawm yog zoo sib xws hauv cov txheej txheem. Cov txheej txheem ua tiav hauv ob theem. Ua ntej, pyridoxal phosphate siv ib pab pawg ua haujlwm los ntawm cov amino acid, uas ua rau tsim cov keto acid thiab pyridoxamine phosphate. Nyob rau theem thib ob, nws hnov mob nrog α-keto acid, pyridoxal phosphate, cov keto acid sib xws, yog tsim los ua cov khoom kawg. Nyob rau hauv xws li kev sib cuam tshuam, pyridoxal phosphate yog cov cab kuj ntawm cov amino pawg.
Kev hloov pauv ntawm cov amino acids los ntawm cov txheej txheem no tau lees paub los ntawm txoj kev tsom xam spectral. Tam sim no, muaj pov thawj tshiab rau lub xub ntiag ntawm xws li ib tug mechanism nyob rau hauv creatures.
Tus nqi hauv kev pauv pauv
Lub luag haujlwm ntawm amino acid transamination ua si li cas? Tus nqi ntawm cov txheej txheem no yog qhov loj heev. Cov tshuaj tiv thaiv no muaj nyob rau hauv cov nroj tsuag thiab cov kab mob, nyob rau hauv cov ntaub so ntswg tsiaj vim lawv siab tsis kam mus rau tshuaj, lub cev,Cov yam ntxwv lom neeg, qhov tseeb stereochemical tshwj xeeb hauv kev sib raug zoo rau D- thiab L-amino acids.
Lub ntsiab lus lom neeg ntawm kev hloov pauv ntawm cov amino acids tau raug tshuaj xyuas los ntawm ntau tus kws tshawb fawb. Nws tau dhau los ua cov ntsiab lus ntawm kev kawm ntxaws hauv cov txheej txheem metabolic amino acid. Hauv chav kawm ntawm kev tshawb fawb, ib qho kev xav tau muab tso rau pem hauv ntej txog qhov ua tau ntawm cov txheej txheem ntawm transamination ntawm amino acids siv transdeamination. Euler tshawb pom tias hauv cov tsiaj cov ntaub so ntswg tsuas yog L-glutamic acid deaminated los ntawm cov amino acids ntawm tus nqi siab, cov txheej txheem raug catalyzed los ntawm glutamate dehydrogenase.
Cov txheej txheem ntawm deamination thiab transamination ntawm glutamic acid yog cov tshuaj tiv thaiv rov qab.
kho mob tseem ceeb
Yuav siv cov amino acid transamination li cas? Qhov tseem ceeb ntawm cov txheej txheem no yog nyob ntawm qhov muaj peev xwm ua qhov kev sim tshuaj. Piv txwv li, cov ntshav ntshav ntawm tus neeg noj qab haus huv muaj li ntawm 15 mus rau 20 units ntawm transaminases. Nyob rau hauv cov ntaub ntawv ntawm cov ntaub so ntswg kab mob, kev puas hlwb raug soj ntsuam, uas ua rau tso tawm ntawm transaminases mus rau hauv cov ntshav los ntawm qhov txhab.
Nyob rau hauv cov ntaub ntawv ntawm myocardial infarction, lus tom qab 3 teev, theem ntawm aspartate aminotransferase nce mus rau 500 units.
Yuav siv cov amino acid transamination li cas? Biochemistry suav nrog kev sim transaminase, raws li cov txiaj ntsig ntawm tus neeg mob tau kuaj pom, thiab xaiv cov kev kho mob uas tau txheeb xyuas tau zoo.
Cov khoom siv tshwj xeeb yog siv rau kev kuaj mob hauv tsev kho mobCov tshuaj rau kev tshawb nrhiav sai ntawm lactate dehydrogenase, creatine kinase, kev ua haujlwm transaminase.
Hypertransaminasemia yog pom nyob rau hauv cov kab mob ntawm lub raum, daim siab, pancreas, nrog rau cov mob hnyav carbon tetrachloride lom.
1 Transamination thiab deamination ntawm cov amino acids tau siv hauv kev kuaj mob niaj hnub los tshawb xyuas cov hlab ntshav kom pom. Qhov no yog vim qhov nce siab ntawm alanine aminotransferase hauv qee qhov teeb meem siab.
Cov neeg koom nrog kev sib tham
Glutamic acid muaj lub luag haujlwm tshwj xeeb hauv cov txheej txheem no. Kev faib tawm thoob plaws hauv cov nroj tsuag thiab tsiaj cov ntaub so ntswg, stereochemical tshwj xeeb rau cov amino acids, thiab kev ua haujlwm catalytic tau ua rau kev hloov pauv hauv cov kev tshawb fawb hauv cov chaw soj ntsuam. Tag nrho cov amino acids ntuj (tshwj tsis yog methionine) cuam tshuam nrog α-ketoglutaric acid thaum lub sij hawm transamination, ua rau tsim ntawm keto- thiab glutamic acid. Nws nkag mus deamination nyob rau hauv qhov kev txiav txim ntawm glutamate dehydrogenase.
Oxidative deamination xaiv
Muaj ncaj qha thiab tsis ncaj ntawm cov txheej txheem no. Direct deamination suav nrog kev siv ib qho enzyme ua ib qho catalyst; cov khoom siv tshuaj tiv thaiv yog keto acid thiab ammonia. Cov txheej txheem no tuaj yeem ua tiav hauv txoj kev aerobic, piv txwv tias muaj cov pa oxygen, lossis hauv txoj kev anaerobic (tsis muaj oxygen molecules).
Txheej txheem ntawm oxidative deamination
D-oxidases ntawm amino acids ua raws li catalysts ntawm cov txheej txheem aerobic, thiab oxidases ntawm L-amino acids yuav ua raws li coenzymes. Cov tshuaj no muaj nyob rau hauv tib neeg lub cev, tab sis lawv qhia tsawg kawg nkaus kev ua si.
Anaerobic variant ntawm oxidative deamination yog ua tau rau glutamic acid, glutamate dehydrogenase ua raws li catalyst. Cov enzyme no muaj nyob rau hauv mitochondria ntawm tag nrho cov kab mob nyob.
Indirect oxidative deamination, ob theem yog qhov txawv. Ua ntej, cov amino pawg yog pauv los ntawm thawj molecule mus rau keto compound, ib tug tshiab keto thiab amino acids yog tsim. Tsis tas li ntawd, ketoskeleton catabolizes nyob rau hauv ib txoj kev, koom nyob rau hauv lub tricarboxylic acid voj voog thiab cov ntaub so ntswg ua pa, cov khoom kawg yuav yog dej thiab carbon dioxide. Nyob rau hauv cov ntaub ntawv ntawm kev tshaib kev nqhis, cov pob txha pob txha ntawm glucogenic amino acids yuav raug siv los tsim cov piam thaj molecules hauv gluconeogenesis.
theem thib ob cuam tshuam nrog kev tshem tawm ntawm pawg amino los ntawm deamination. Hauv tib neeg lub cev, cov txheej txheem zoo sib xws tsuas yog ua tau rau glutamic acid. Raws li qhov tshwm sim ntawm qhov kev cuam tshuam no, α-ketoglutaric acid thiab ammonia raug tsim.
Zoo kawg
Kev txiav txim siab ntawm kev ua haujlwm ntawm ob lub enzymes ntawm kev hloov pauv ntawm aspartate aminotransferase thiab alanine aminotransferase tau pom daim ntawv thov hauv tshuaj. Cov enzymes no tuaj yeem thim rov qab cuam tshuam nrog α-ketoglutaric acid, hloov cov amino pawg ntawm cov amino acids mus rau nws,tsim keto compounds thiab glutamic acid. Txawm hais tias qhov kev ua haujlwm ntawm cov enzymes no nce rau cov kab mob ntawm cov leeg nqaij thiab daim siab, qhov siab tshaj plaws kev ua haujlwm tau pom hauv cov ntshav ntshav rau AST, thiab rau ALT hauv kab mob siab.
Amino acids yog qhov tseem ceeb hauv kev sib txuas ntawm cov protein molecules, nrog rau kev tsim ntawm ntau lwm cov tshuaj lom neeg lom neeg uas tuaj yeem tswj cov txheej txheem metabolic hauv lub cev: cov tshuaj hormones, neurotransmitters. Tsis tas li ntawd, lawv yog cov pub dawb ntawm nitrogen atoms hauv kev sib txuas ntawm cov khoom tsis muaj protein ntau nitrogen, suav nrog choline, creatine.
Ketabolism ntawm amino acids tuaj yeem siv los ua lub zog rau kev sib txuas ntawm adenosine triphosphoric acid. Lub zog ua haujlwm ntawm cov amino acids muaj txiaj ntsig tshwj xeeb hauv cov txheej txheem kev tshaib plab, nrog rau cov ntshav qab zib mellitus. Amino acid metabolism tso cai rau koj los tsim kev sib txuas ntawm ntau yam tshuaj hloov pauv uas tshwm sim hauv cov kab mob muaj sia.
Tib neeg lub cev muaj txog 35 grams dawb amino acids, thiab lawv cov ntshav cov ntsiab lus yog 3565 mg / dL. Ib qho loj ntawm lawv nkag mus rau hauv lub cev los ntawm cov zaub mov, ntxiv rau, lawv nyob hauv lawv cov ntaub so ntswg, lawv tuaj yeem tsim los ntawm carbohydrates.
Nyob hauv ntau lub hlwb (tshwj tsis yog erythrocytes) lawv tau siv tsis yog rau kev tsim cov protein, tab sis kuj tsim cov purine, pyrimidine nucleotides, biogenic amines, membrane phospholipids.
Nyob ib hnub, kwv yees li 400 g ntawm cov protein sib txuas ua rau cov amino acids hauv tib neeg lub cev, thiab cov txheej txheem rov qab tshwm sim nyob rau hauv kwv yees li qub.
NpajCov proteins tsis muaj peev xwm ua tiav cov nqi ntawm cov amino acids rau kev sib txuas ntawm lwm cov organic tebchaw nyob rau hauv rooj plaub ntawm catabolism.
Nyob rau hauv cov txheej txheem ntawm evolution, tib neeg tau poob lub peev xwm los tsim ntau cov amino acids ntawm nws tus kheej, yog li ntawd, thiaj li yuav muab lub cev nrog lawv nyob rau hauv tag nrho, nws yog ib qhov tsim nyog yuav tau txais cov nitrogen-muaj cov tebchaw los ntawm cov zaub mov.. Cov txheej txheem tshuaj lom neeg uas cov amino acids koom nrog tseem yog kev kawm los ntawm kws tshuaj thiab kws kho mob.
