I-CYANOCOBALAMIN (IVITAMINI B12)
Isimo kanye nezakhiwo
Lo mkhiqizo uyi-crimson crystal noma i-crystalline powder, awunaphunga, awunambitheki futhi unezakhiwo ezinamandla ezibangela umswakama. Uncibilika kancane emanzini noma e-ethanol, awuncibiliki ku-chloroform noma ku-ether. Umelana nokushisa, kodwa ungangasebenzi uma ubhekene nezinto ezikhipha i-oxidizing noma ezinciphisayo (njenge-vitamin C noma i-hydrogen peroxide, njll.), usawoti wensimbi esindayo kanye nama-acid aqinile kanye nama-alkali aqinile.
Isakhiwo Samakhemikhali
I-Vitamin B12 iyinhlanganisela ye-equioctaphedral equkethe ama-ion e-cobalt. Isakhiwo sayo esiphakathi siyindandatho eyisicaba ye-corrin eyakhiwe ngama-pyrroles amane axhunyiwe. Ama-molecule e-vitamin B12 akhiwe cishe izingxenye ezintathu: indandatho ye-gourin e-chylated ngama-athomu amane e-N nama-ion e-cobalt aphakathi; ama-5,6-dimethylbenzimidazole (5,6-dimethylbenzimidazole, DMBI) axhunywe kuma-athomu e-N-7 nama-ion e-cobalt njengama-molecule e-vitamin B 12 ama-ligands aphansi (α). Ngaphezu kwalokho, i-DMBI ixhunywe futhi kuma-aminopropanol ngamaqembu e-phosphate, kanti i-aminopropanol ixhunywe ndawonye neketanga eliseceleni le-propionic acid ku-pyrrole D; iqembu le-adenosyl noma iqembu le-methyl. Ixhunywe nama-ion e-cobalt ukwakha i-ligand ephezulu (β) yama-molecule e-vitamin B12. Izinhlobo ezahlukene zezinto ze-vitamin B12 zakhiwa lapho iqembu lencwadi yamakhemikhali lihlukile encwadini yamakhemikhali ephezulu ku-axis yendandatho ye-goline. Iqembu le-hydroxyl (-OH) lixhunywe kwi-ion ye-cobalt esendandatho ye-gluline ukuze kwakhiwe i-hydroxycobalamin. Ngokufanayo, i-deoxyadenosine (5'-deoxyadenosyl), i-methyl (-CH3), i-cyanide (-CN) kanye nama-ion e-cobalt axhunyiwe ukuze kukhiqizwe i-adenosine cobalt ngokulandelana. I-Amine (deoxyadenosylcobalamin), i-methylcobalamin (methylcobalamin) kanye ne-cyanocobalamin (cyanocobalamin). Ngokwemvelo, uhlobo lokugcina lwe-biosynthesis ye-vitamin B12 yi-microorganisms yi-adenosine cobalamine (i-coenzyme B12), i-methyl cobalamine kanye ne-hydroxycobalamine. Kodwa-ke, ngenxa yokuthi izakhiwo zazo azizinzile kakhulu, i-sodium cyanide ingezwa ngokwenziwa enkambisweni yokuhlanzwa kwezimboni ukuze kuguqulwe uhlobo lwemvelo lwe-vitamin B12 lube yi-cyanocobalamin ezinzile kakhulu.
Umsebenzi Wezinto Eziphilayo
Thuthukisa izinga lokusetshenziswa kwe-folic acid, ukwenziwa kwe-meththionine (okwenziwa kusuka ku-cysteineine ephezulu) kanye ne-choline nge-folic acid, kanye nokwakhiwa kwe-cyanocobalamin precursors njenge-methyl coballamin kanye ne-coenzyme B12 enkambisweni yokukhiqiza i-prine kanye ne-pyrimidine, futhi uhlanganyele enkambisweni ye-methylation yamakhemikhali amaningi abalulekile. Uma i-vitamin B12 intula, umsebenzi wokudlulisa amaqembu e-methyl kusuka ku-methyl tetrahydrofolic acid uyancishiswa, okwenza i-folic acid ibe yindlela engasetshenziswa, okuholela ekuntuleni i-folic acid. Gcina i-metabolism kanye nomsebenzi we-nerve myelin sheath. Ukuntuleka kwe-vitamin B12 kungabangela ukuphazamiseka kwezinzwa, ukuwohloka komgogodla, kanye ne-chemical book kungabangela izimpawu ezinkulu zengqondo. Ukuntuleka kwe-Vitamin B12 kungaholela ku-peripheral neuritis. Ukubonakaliswa kokuqala kokuntuleka kwe-vitamin B12 ezinganeni yimizwa engavamile, ukuvezwa okuvilaphayo, ukusabela kancane, futhi ekugcineni kuholele ku-anemia. Khuthaza ukuthuthukiswa nokuvuthwa kwamaseli abomvu egazi. I-Methylpropandiyl coenzyme A iguqulwa ibe yi-succinoyl coenzyme A futhi ihlanganyela emjikelezweni we-tricarboxylic acid, lapho i-succinyl coenzyme A ihlobene nokwakheka kwe-heme. I-Vitamin B12 ihlanganyela futhi ekwakhiweni kwe-deoxynucleic acid (DNA), ekusetshenzisweni kwamafutha, ama-carbohydrate namaprotheni, futhi ikhulisa ukwakheka kwama-nucleic acid namaprotheni.
