Qhov sib txawv tseem ceeb ntawm cysteine thiab selenocysteine yog tias cysteine yog ib qho proteinogenic amino acid uas muaj leej faj hauv nws cov qauv, thaum selenocysteine yog proteinogenic amino acid uas muaj selenium hauv nws cov qauv.
YCysteine thiab selenocysteine yog ob proteinogenic amino acids. Proteinogenic amino acids yog cov amino acids koom ua ke rau hauv cov proteins thaum lub sijhawm kev txhais lus. Lawv yog qhov tseem ceeb heev rau biosynthesis ntawm cov protein ua haujlwm. Muaj 22 genetic encoded proteinogenic amino acids thoob plaws hauv lub neej paub. Nees nkaum amino acids yog nyob rau hauv tus txheej txheem genetic code, thiab ob tug yuav muab tso ua ke los ntawm ib tug tshwj xeeb translational mechanism. Ntawm cov proteinogenic amino acids, cuaj amino acids yog qhov tseem ceeb, thiab cov amino acids seem tsis tseem ceeb.
YCysteine yog dab tsi?
Cysteine yog ib qho tseem ceeb ntawm cov proteinogenic amino acid uas muaj leej faj hauv nws cov qauv. Nws muaj cov tshuaj formula ntawm HOOC-CH-(NH2)-CH2-SH. Lub thiol sab saw ntawm cysteine nquag koom nrog biochemical enzymatic cov tshuaj tiv thaiv raws li nucleophile. Cov pab pawg thiol tuaj yeem ua rau cov tshuaj tiv thaiv redox. Yog li, cysteine muaj cov tshuaj antioxidant. Cysteine cov cuab yeej antioxidant feem ntau yog qhia hauv tripeptide glutathione, tus tswv antioxidant hauv tib neeg lub cev. Cysteine encoded los ntawm cov noob caj noob ces codons UGU thiab UGC. Thaum siv los ua zaub mov ntxiv, nws muaj tus lej E ntawm E920.
Daim duab 01: Cysteine
Cysteine muaj nyob hauv zwitterion zoo li lwm cov amino acids. Cysteine yog ib qho seem seem hauv cov zaub mov muaj protein ntau. Tej zaum nws yuav yog ib qho tseem ceeb rau cov me nyuam mos, cov laus, thiab lwm tus neeg uas muaj malabsorption syndromes. Cysteine tuaj yeem nquag tsim los ntawm tib neeg lub cev yog tias muaj cov methionine txaus. Cysteine yog industrially tau los ntawm hydrolysis ntawm tsiaj cov ntaub ntawv xws li nqaij qaib feathers los yog hog plaub hau. Tsis tas li ntawd, cysteine muaj ntau yam kev ua haujlwm lom neeg xws li precursor rau antioxidant glutathione, precursor rau hlau-sulfur pawg, hlau hlau-binding khoom, lub luag haujlwm tseem ceeb hauv cov qauv protein, thiab lwm yam.
Selenocysteine yog dab tsi?
Selenocysteine yog ib qho proteinogenic amino acid uas muaj selenium hauv nws cov qauv. Nws yog structurally heev zoo ib yam li cysteine. Selenocysteine yog 21 st amino acid. Ob leeg eukaryotes thiab prokaryotes tuaj yeem koom nrog selenocysteine rau hauv lawv cov proteins los ntawm cov kab ke nucleotide hu ua "SECIS element". Qhov no coj cov hlwb los txhais cov lus nyob ze UGA codon (feem ntau nres codon) li selenocysteine. Cov proteinogenic amino acid no muaj nyob hauv ntau cov enzymes, suav nrog glutathione peroxidase, tetraiodothyronine 5' deiodinases, thioredoxin reductases, formate dehydrogenases, glycine reductases, selenophosphate synthetase 2, methionine R sulfoxide reductase B1s, thiab qee qhov hydrogenase. Ntxiv mus, selenocysteine tau pom thawj zaug los ntawm biochemist Thressa Stadtman ntawm National Institute of He alth.
Daim duab 02: Selenocysteine
Tam sim no, 136 tib neeg cov proteins paub tias muaj selenocysteine. Tsis tas li ntawd, nws tau siv biotechnologically hauv 73 Se-lablled Sec hauv txoj haujlwm emission tomography (PET), 75 Se-labelled Sec hauv cov xov tooj cua tshwj xeeb thiab 77Se isotope hauv high-resolution NMR.
Dab tsi zoo sib xws ntawm Cysteine thiab Selenocysteine ?
- Cysteine thiab selenocysteine yog ob proteinogenic amino acids.
- Ob leeg muaj cov qauv zoo sib xws.
- Cov no yog cov kua qaub amino acids.
- Lawv yog tsim los ntawm tib neeg lub cev.
- Lawv muaj nyob rau hauv ob qho tib si prokaryotes thiab eukaryotes.
Qhov txawv ntawm Cysteine thiab Selenocysteine yog dab tsi?
Cysteine yog ib qho proteinogenic amino acid uas muaj leej faj hauv nws cov qauv, thaum selenocysteine yog proteinogenic amino acid uas muaj selenium hauv nws cov qauv. Yog li, qhov no yog qhov sib txawv tseem ceeb ntawm cysteine thiab selenocysteine . Ntxiv mus, cysteine yog coded los ntawm cov noob caj noob ces codons UGU thiab UGC, thaum selenocysteine coded los ntawm cov noob caj noob ces codon UGA.
Cov hauv qab no infographic teev ntau qhov sib txawv ntawm cysteine thiab selenocysteine nyob rau hauv daim ntawv tabular rau ib sab ntawm kev sib piv.
Summary – Cysteine vs Selenocysteine
YCysteine thiab selenocysteine yog ob proteinogenic amino acids. Lawv tau muab tso rau hauv biosynthetically rau hauv cov proteins thaum lub sijhawm txhais lus. Cysteine muaj sulfur hauv nws cov qauv, thaum selenocysteine muaj selenium hauv nws cov qauv. Yog li, qhov no qhia txog qhov sib txawv ntawm cysteine thiab selenocysteine.
