Ib tus kws tshawb fawb nto moo ib zaug tau hais tias: "Lub neej yog ib hom kev muaj nyob ntawm lub cev protein." Thiab nws yog tiag tiag, vim hais tias nws yog cov organic tshuaj uas yog lub hauv paus ntawm feem ntau cov kab mob. Quaternary qauv protein muaj cov txheej txheem nyuaj tshaj plaws thiab cov khoom tshwj xeeb. Peb tsab xov xwm yuav mob siab rau nws. Peb kuj tseem yuav xav txog cov qauv ntawm cov protein molecules.
Dab tsi yog organic teeb meem
Ib pawg loj ntawm cov tshuaj organic yog koom ua ke los ntawm ib qho khoom vaj khoom tsev. Lawv yog tsim los ntawm ntau yam tshuaj. Lawv hu ua organic. Cov no yog hydrogen, oxygen, carbon thiab nitrogen. Lawv tsim cov organic.
Lwm qhov tshwj xeeb yog tias lawv yog txhua tus biopolymers. Cov no yog cov macromolecules loj. Lawv yog tsim los ntawm ntau cov khoom siv rov ua dua hu ua monomers. Rau cov carbohydrates, cov no yog monosaccharides, rau lipids, glycerol thiab fatty acids. Tab sis DNA thiab RNA yog tsim los ntawm nucleotides.
TshuajCov qauv ntawm cov proteins
Protein monomers yog cov amino acids, txhua tus muaj nws cov qauv tshuaj. Cov monomer no yog ua raws li carbon atom, nws tsim plaub daim ntawv cog lus. Thawj ntawm lawv - nrog hydrogen atom. Thiab qhov thib ob thiab thib peb, raws li, yog tsim nrog cov amino thiab carbox pawg. Lawv txiav txim siab tsis tsuas yog cov qauv ntawm biopolymer molecules, tab sis kuj lawv cov khoom. Cov pab pawg kawg hauv cov amino acid molecule hu ua radical. Qhov no yog raws nraim pawg ntawm cov atoms uas txhua tus monomers txawv ntawm ib leeg, uas ua rau muaj ntau yam proteins thiab tsiaj nyob.
qauv ntawm cov protein molecule
Ib qho ntawm cov yam ntxwv ntawm cov organics yog tias lawv tuaj yeem muaj nyob ntawm ntau theem ntawm lub koom haum. Qhov no yog thawj, theem nrab, tertiary, quaternary qauv ntawm cov protein. Txhua tus ntawm lawv muaj qee yam khoom thiab zoo.
qauv qauv
Cov qauv protein no yog qhov yooj yim tshaj plaws hauv cov qauv. Nws yog cov saw ntawm cov amino acids txuas los ntawm peptide bonds. Lawv raug tsim los ntawm cov amino thiab carboxy pawg ntawm cov nyob sib ze molecules.
qauv tsev kawm theem nrab
Thaum cov saw hlau ntawm cov amino acids coils rau hauv helix, cov qauv thib ob ntawm cov protein tau tsim. Daim ntawv cog lus nyob rau hauv xws li ib tug molecule yog hu ua hydrogen, thiab nws cov atoms tsim tib lub ntsiab nyob rau hauv lub functional pawg ntawm amino acids. Piv rau peptides, lawv muaj zog tsawg dua, tab sis muaj peev xwm tuav tau cov qauv no.
Tertiary structure
Tab sis cov qauv tom ntej yog lub pob uas muaj kauv ntawm cov amino acids twisted. Nws tseem hu ua globule. Nws tshwm sim los ntawm kev sib cog lus uas tshwm sim ntawm cov seem ntawm tsuas yog ib qho amino acid - cysteine . Lawv hu ua disulfides. Cov qauv no kuj tau txais kev txhawb nqa los ntawm hydrophobic thiab electrostatic bonds. Cov qub yog qhov tshwm sim ntawm kev nyiam ntawm cov amino acids nyob rau hauv ib puag ncig dej. Nyob rau hauv cov xwm txheej zoo li no, lawv cov residues hydrophobic xyaum "sau ua ke", tsim ib lub globule. Tsis tas li ntawd, cov amino acid radicals muaj cov nqi sib txawv uas nyiam ib leeg. Qhov no ua rau cov nyiaj electrostatic ntxiv.
Protein ntawm quaternary qauv
Cov qauv quaternary ntawm cov protein yog qhov nyuaj tshaj plaws. Qhov no yog qhov tshwm sim ntawm kev sib koom ua ke ntawm ntau lub globules. Lawv tuaj yeem sib txawv ob qho tib si hauv tshuaj muaj pes tsawg leeg thiab hauv lub koom haum spatial. Yog tias cov protein ntawm cov qauv quaternary tsuas yog tsim los ntawm cov amino acid residues, nws yooj yim. Xws li biopolymers tseem hu ua cov proteins. Tab sis yog tias cov khoom tsis yog cov protein txuas nrog cov molecules, cov proteins tshwm sim. Feem ntau, qhov no yog kev sib xyaw ntawm cov amino acids nrog carbohydrates, nucleic thiab phosphoric acid residues, lipids, ib tus neeg hlau thiab tooj liab atoms. Nyob rau hauv cov xwm, complexes ntawm cov proteins nrog ntuj xim tshuaj - pigments kuj paub. Cov qauv ntawm cov protein molecules no complex.
Daim ntawv spatial ntawm cov qauv quaternary ntawm cov protein yogtxhais nws cov khoom. Cov kws tshawb fawb tau pom tias filamentous lossis fibrillar biopolymers tsis yaj hauv dej. Lawv ua haujlwm tseem ceeb rau cov kab mob muaj sia. Yog li, cov leeg nqaij proteins actin thiab myosin muab lub zog, thiab keratin yog lub hauv paus ntawm tib neeg thiab tsiaj plaub hau. Spherical los yog globular proteins ntawm lub quaternary qauv yog heev soluble nyob rau hauv dej. Lawv lub luag haujlwm hauv qhov xwm txheej txawv. Cov tshuaj no tuaj yeem thauj cov pa roj xws li ntshav hemoglobin, zom cov zaub mov zoo li pepsin, lossis ua haujlwm tiv thaiv zoo li cov tshuaj tiv thaiv.
YProtein Properties
A quaternary protein, tshwj xeeb tshaj yog ib lub ntiaj teb, tuaj yeem hloov nws cov qauv. Cov txheej txheem no tshwm sim nyob rau hauv kev cuam tshuam ntawm ntau yam. Cov no feem ntau yog kub, concentrated acids, los yog hnyav hlau.
Yog hais tias cov protein molecule unwinds mus rau ib tug saw ntawm amino acids, cov cuab yeej no hu ua denaturation. Cov txheej txheem no yog thim rov qab. Cov qauv no tuaj yeem tsim cov globules ntawm cov molecules dua. Txoj kev thim rov qab no hu ua renaturation. Yog hais tias cov amino acid molecules txav deb ntawm ib leeg thiab peptide bonds tawg, degradation tshwm sim. Cov txheej txheem no yog irreversible. Xws li cov protein tsis tuaj yeem rov qab los. Kev puas tsuaj yog ua los ntawm peb txhua tus thaum peb kib qe.
Yog li, cov qauv quaternary ntawm cov protein yog hom kev sib cog lus uas tau tsim nyob rau hauv ib qho molecule. Nws muaj zog txaus, tab sis nyob rau hauv kev cuam tshuam ntawm qee yam nws tuaj yeem tawg.
