Aliphatic amino acids - derivatives ntawm carboxylic acids - yog dav faib nyob rau hauv cov xwm. Lawv ua lub luag haujlwm tseem ceeb hauv ntau cov txheej txheem tseem ceeb. Raws li lawv lub hauv paus, qee hom tshuaj tau tsim.
Aliphatic amino acid - yog dab tsi?
Amino acids ua haujlwm tseem ceeb hauv tib neeg lub cev thiab lwm yam tsiaj, vim tias lawv yog cov tshuaj neurotransmitters thiab "tsev blocks" tsim cov proteins. Lawv kuj xav tau rau cov metabolism kom zoo.
Aliphatic amino acids yog ntau yam aminocarboxylic amino acids uas cov amino thiab carboxyl pawg tau sib koom ua ke rau aliphatic carbon atom. Lo lus "aliphatic" yog hais txog cov kab los yog cov saw hlau ntawm cov atoms ntawm cov khoom muab.
Cov amino acids ntau uas tau muab cais tawm ntawm cov kab mob muaj sia yog aliphatic. Hauv chemistry, lawv feem ntau siv cov npe niaj hnub ntawm cov tshuaj no raws li cov proteins qub uas lawv tau txais, txij li raws li cov txheej txheem nomenclature lawv muaj cov npe cumbersome dhau lawm.
Hom kev sib txuas los ntawm cov qauv
Aliphatic amino acids, nyob ntawm txoj haujlwm ntawm cov amino thiab carboxyl pawg, tau muab faib ua hom hauv qab no:
- Alpha isomers. Cov no suav nrog feem ntau ntawm cov tebchaw uas muaj nyob hauv cov nroj tsuag, kab mob, thiab tsiaj txhu. Lawv kuj pom muaj nyob rau hauv meteorites, thiab cov qauv ntawm cov khoom no yog tib yam li cov tsiaj nyob hauv av.
- Betta-amino acids. Ib qho piv txwv yog β-alanine, uas yog ib feem ntawm coenzyme A. Cov tom kawg yog koom nrog hauv kev sib txuas thiab oxidation ntawm fatty acids.
- Gamma isomers. Ib qho ntawm cov neeg sawv cev zoo tshaj plaws ntawm pab pawg no yog ɣ-aminobutyric acid (GABA), qhov tseem ceeb tshaj plaws neurotransmitter ntawm lub paj hlwb lub luag haujlwm rau inhibition ntawm cov txheej txheem paj hlwb, qhov tsis muaj zog thiab kev tawm tsam ntawm excitation.
Txhua yam alpha-hom amino acids, tshwj tsis yog glycine, muaj cov qauv asymmetric, muaj nyob rau hauv daim ntawv ntawm ob daim iav tsom iav uas tsis sib xyaw hauv qhov chaw (L- thiab D-amino acids) thiab muaj kev ua haujlwm kho qhov muag. L-amino acids tseem ceeb tshaj plaws yog glycine, alanine, serine, cysteine, aspartic acid, tyrosine, leucine, glutamine, isoleucine, arginine, lysine, proline.
Piv txwv ntawm aliphatic amino acids tau qhia hauv daim duab hauv qab no.
Nyob ntawm cov tshuaj raws li lwm yam
Tseem muaj kev faib tawm raws li qhov xwm txheej ntawm kev koom tes ntawm aliphatic amino acids hauv protein synthesis.
- Proteinogenic compounds los ntawm L-series, uas txuas nrog cov proteins hauv ribosomes raws li kev tswj hwm ntawm RNA. Lawvcov kab ke yog genetic encoded. Tsuas muaj nees nkaum cov amino acids xwb.
- Non-proteinogenic (tsis yog-coding), tsis yog ib feem ntawm cov protein, tab sis ua haujlwm tseem ceeb (feem ntau yog kev koom tes hauv cov txheej txheem metabolic). Ib txhia ntawm lawv yog co toxins thiab lom rau tib neeg.
Raws li cov kua qaub-puag, aliphatic amino acids muab faib ua 3 hom:
- acidic (aspartic thiab glutamic acids);
- nruab nrab, muaj tib tus lej ntawm cov pab pawg hauv paus thiab acidic;
- basic (histidine, arginine, lysine thiab lwm yam).
Lub cev thiab tshuaj lom neeg
Cov khoom nram qab no yog qhov raug rau aliphatic amino acids:
- qauv hauv daim ntawv ntawm bipolar ions hauv lub xeev crystalline;
- siab melting point (α-amino acids tsis muaj tus nqi meej);
- zoo solubility hauv dej thiab aqueous daws ntawm alkalis, acids;
- amphoteric;
- cov khoom tseem ceeb hauv ib puag ncig acidic thiab vice versa;
- yog tias pH ntawm qhov nruab nrab siab tshaj qhov taw tes isoelectric, ces aliphatic amino acids tsim cov ntsev nrog alkalis, uas yaj zoo hauv dej.
Kev sib xyaw ntawm cov tshuaj no nrog lawv cov sodium lossis potassium ntsev yog siv los ua cov tshuaj tsis haum siv rau kev tshuaj xyuas tshuaj.
Synthesis
BNyob rau hauv lub chaw soj nstuam, zus tau tej cov cov tebchaw yog ib tug nyuaj ua hauj lwm, vim hais tias lawv yog optically active, thiab nyob rau hauv tej yam ntuj tso tej yam kev mob lawv zus tau tej cov tshwm sim nrog kev koom tes ntawm enzymes. Yog li ntawd, tsuas yog racemic amino acids, uas yog sib xyaw ntawm optical isomers, tau txais tshuaj.
Raws li cov khoom pib, α-halocarboxylic acids yog siv, uas, thaum reacted nrog ammonia, muab aliphatic amino acids. Muaj lwm txoj hauv kev kom tau txais - los ntawm keto acids thiab lawv cov derivatives nyob rau hauv cov txheej txheem ntawm reductive amination, los ntawm malonic ester, aminoacetic acid (glycine). Rau kev sib txuas ntawm cov amino acids ntawm kev lag luam nplai, microbiological technologies yog siv. Nrog kev pab los ntawm genetic engineering, cov tshuaj no yog cais los ntawm cov protein molecules uas tsim los ntawm tshwj xeeb cultivated microorganisms.
Role in nature
Tsuas yog hauv cov nroj tsuag thiab kab mob, ntau dua 200 aliphatic amino acids tau txheeb xyuas, thiab tag nrho muaj ntau tshaj tsib puas ntawm lawv niaj hnub no. Lawv yog ib feem ntawm cov tshuaj tua kab mob (xws li penicillin) uas cov kab mob tsim thiab tsim cov phab ntsa ntawm cov kab mob feem ntau.
Hauv lub cev ntawm cov tsiaj, cov tshuaj no ua cov haujlwm tseem ceeb hauv qab no:
- synthesis ntawm cov proteins, enzymes, cov tshuaj hormones, coenzymes thiab lwm yam tseem ceeb organic compounds;
- tsim cov tshuaj lom neeg lom neeg (dopamine, norepinephrine, epinephrine, serotonin thiab lwm yam);
- kev koom tes hauv kev sib kis ntawm cov hlab ntsha impulses thiab cov txheej txheem metabolic.
Hauv tib neeg lub hlwb hlwb muaj cov metabolism hauv kev ua haujlwm nrog kev koom tes ntawm cov amino acids, qhov concentration ntawm 7 npaug ntau dua li cov ntshav plasma.
daim ntawv thov kho mob
Kev siv cov tshuaj no rau kev kho mob yog nyob ntawm lawv lub peev xwm los koom nrog kev sib pauv ntawm cov ntsiab lus nitrogenous thiab kev sib txuas ntawm cov tshuaj lom neeg lom neeg. Muaj ntau cov tshuaj uas muaj aliphatic amino acids. Cov npe hauv qab no yog qee qhov ntawm lawv thiab lawv siv hauv kev xyaum kho mob.
- Glutamic acid - CNS pathology, qaug dab peg, psychosis, hlwb retardation rau cov me nyuam, cerebral palsy, Down's disease.
- Methionine - toxic siab puas tsuaj (cirrhosis, lom nrog arsenic, chloroform thiab lwm yam co toxins), nrog rau cov kab mob ntawm cov kabmob no hauv kev haus dej cawv, mob ntshav qab zib mellitus.
- Aminalone yog tus neeg sawv cev neurotropic.
- Cysteine - rau cataracts.
- Acetylcysteine - nyob rau hauv cov kab mob ntawm cov kab mob ua pa ua mucolytic.
