Qhov Tseem Ceeb - L vs D Amino Acids
L amino acids thiab D amino acids yog ob hom amino acids. Qhov sib txawv tseem ceeb ntawm L thiab D amino acids yog tias L amino acid yog lub enantiomer ntawm ib qho amino acid uas muaj peev xwm tig lub dav hlau polarized lub teeb anticlockwise (sab laug-tes) whereas D amino acid yog enantiomer ntawm cov amino acid uas muaj peev xwm. ntawm rotating dav hlau polarized teeb clockwise (sab xis sab xis).
Ib qho amino acid tsuas yog ib qho organic molecule nrog cov amino pawg yooj yim (-NH 2), ib pawg acidic carboxyl (-COOH), proton thiab qhov sib txawv 'R ' pawg khi rau sp3 hybridized central carbon atom. Qhov sib txawv hauv pawg R qhia txog cov tshuaj sib txawv rau cov amino acids thiab qhov ua tau loj ntawm cov pab pawg tshuaj uas tuaj yeem khi rau hauv nruab nrab cov pa roj carbon atom raws li R pawg yields ib qho zoo kawg li ntau haiv neeg ntawm cov amino acids nrog ib tug loj versatility. Amino acids paub zoo tias yog cov txheej txheem subunits uas tsim cov proteins. Lawv kuj ua hauj lwm raws li nruab nrab ntawm cellular metabolism.
Chirality yog dab tsi?
Chirality ntawm ib qho organic compound yog tshwm sim los ntawm ib los yog ntau tshaj chiral carbons nyob rau hauv cov organic molecule. Ib 'chiral carbon' yog ib qho asymmetric carbon atom txuas rau plaub hom atoms lossis tshuaj lom neeg. Tam sim no, tag nrho cov alpha-amino acids - tshwj tsis yog glycine uas muaj ob qhov sib txawv ntawm hydrogen atoms khi rau alpha carbon - muaj chiral alpha carbons. Cov chiral alpha carbons tso cai rau stereoisomerism, thiab yog li ntawd, tag nrho cov physiological alpha amino acids tshwj tsis yog glycine tuaj yeem tsim ob lub stereoisomers txhua, uas yog daim iav duab ntawm ib leeg. Cov duab iav uas tsis yog superimposable no yog hu ua 'enantiomers' thiab lub npe hu ua 'L' lossis 'D' (L / D nomenclature) lossis 'N' lossis 'S' (N / S nomenclature). Txawm hais tias tus nomenclature, qhov sib txawv enantiomeric no yog qhov tseem ceeb ntawm kev lom neeg vim tias cov amino acids cuam tshuam nrog cov molecules rhiab heev uas tuaj yeem paub txog tsuas yog ob qho ua tau enantiomers.
L Amino Acid yog dab tsi?
Ib L amino acid yog enantiomer uas, thaum nyob rau hauv ib qho kev daws, rotates dav hlau polarized lub teeb anticlockwise. Tsab ntawv 'L' qhia lo lus Latin 'Laevus', uas txhais tau tias 'sab laug'. Qhov kev sib hloov no yog hu ua 'kev ua haujlwm kho qhov muag' thiab ntsuas siv cov cuab yeej hu ua 'polarimeter'. Txawm hais tias muaj cov ntawv L thiab D, qhov xav tsis thoob hauv cov protein ntau hauv lub cev, tsuas yog L amino acids pom, thiab vim li ntawd, feem ntau cov amino acids ib txwm muaj L-enantiomeric ntau dhau hauv cov kab mob lom.
D Amino Acid yog dab tsi?
A D-amino acid yog tus enantiomer ntawm ib qho amino acid uas muaj peev xwm tig lub dav hlau polarized lub teeb clockwise. Incorporating lo lus Latin 'Dexter' - lub ntsiab lus 'txoj cai' - cov enantiomers no hu ua D-enantiomers. Feem ntau, D-amino acids tsis tsim thiab koom ua ke rau hauv cov proteins los ntawm cov kab ke ntawm tes. Txawm li cas los xij, qee qhov D-amino acids tuaj yeem pom hauv cov phab ntsa ntawm cov kab mob hauv cov kab mob, tab sis qhov nthuav, tsis yog nyob rau hauv cov kab mob proteins.
Daim duab 1: L thiab D Alanine
Txawm hais tias D-amino acids tsis tshua muaj nyob rau hauv cov kab mob lom, muaj ntau zaus uas D cov ntaub ntawv ua lub luag haujlwm tseem ceeb. Ib qho piv txwv yog kev ua ntawm racemase enzyme ntawm Vibro cholera uas, thaum lub sij hawm loj hlob qeeb, tsim D cov ntaub ntawv ntawm methionine thiab leucine los ntawm lawv cov L counterparts uas txo cov peptidoglycan ntau lawm.
Kev sib raug zoo ntawm L thiab D Amino Acids yog dab tsi?
L thiab D amino acids yog enantiomers ntawm ib leeg
Qhov txawv ntawm L thiab D Amino Acids yog dab tsi?
YL vs D Amino Acids |
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| L amino acid yog enantiomer ntawm cov amino acid uas muaj peev xwm tig lub dav hlau polarized lub teeb anticlockwise. | D amino acid yog enantiomer ntawm ib qho amino acid uas muaj peev xwm tig lub dav hlau polarized lub teeb clockwise. |
| Tsab ntawv "L" ntawm L amino acid txhais tau tias "Laevus". | Tsab ntawv "D" ntawm L amino acid txhais tau tias "Dexter". |
| Nyob rau hauv feem ntau physiological proteins, tsuas yog L amino acids pom. | Qee D-amino acids tuaj yeem pom cov kab mob ntawm cov phab ntsa ntawm tes, tsis nyob hauv cov kab mob proteins. |
Summary – L vs D Amino Acids
Amino acids yog lub tsev tsim cov proteins. Muaj ob hom enantiomers ntawm cov amino acids: L amino acids thiab D amino acids. Qhov sib txawv tseem ceeb ntawm L thiab D amino acids yog tias L amino acid yog lub enantiomer ntawm ib qho amino acid uas muaj peev xwm tig lub dav hlau polarized lub teeb anticlockwise los yog rau sab laug-sab laug whereas D amino acid yog enantiomer ntawm cov amino acid uas yog. muaj peev xwm tig dav hlau polarized lub teeb clockwise los yog mus rau sab xis.
