CYANOCOBALAMIN (VITAMIN B12)
Cov Duab thiab Cov Khoom
Cov khoom no yog xim liab dawb los yog hmoov crystalline, tsis muaj ntxhiab, tsis qab thiab muaj zog ua rau noo noo. Yaj me ntsis hauv dej lossis ethanol, tsis yaj hauv chloroform lossis ether. Tiv taus kub, tab sis nws yuav tsis zoo thaum raug rau cov tshuaj oxidizing lossis txo (xws li vitamin C lossis hydrogen peroxide, thiab lwm yam), ntsev hlau hnyav thiab cov kua qaub muaj zog thiab cov alkali muaj zog.
Cov Qauv Tshuaj
Vitamin B12 yog ib qho equioctaphedral compound uas muaj cobalt ions. Nws lub hauv paus qauv yog ib lub nplhaib corrin tiaj tus uas muaj plaub lub pyrroles txuas nrog. Cov molecules ntawm vitamin B12 yog kwv yees li ntawm 3 qhov chaw: ib lub nplhaib gourin chylated los ntawm plaub N atoms thiab central cobalt ions; 5,6-dimethylbenzimidazole (5,6-dimethylbenzimidazole, DMBI) txuas nrog N-7 atoms thiab cobalt ions ua vitamin B 12 molecules ntawm qib qis (α) ligands. Tsis tas li ntawd, DMBI kuj txuas nrog aminopropanol los ntawm phosphate pawg, thiab aminopropanol yog covalently txuas nrog propionic acid sab saw ntawm pyrrole D; adenosyl pawg lossis methyl pawg Nws txuas nrog cobalt ions los tsim cov sab saud (β) ligand ntawm vitamin B12 molecules. Ntau hom vitamin B12 tshuaj yog tsim thaum pawg ntawm phau ntawv tshuaj txawv ntawm phau ntawv tshuaj sab saud ntawm lub axis ntawm goline nplhaib. Pawg hydroxyl (-OH) txuas nrog cov cobalt ion hauv lub nplhaib gluline los tsim hydroxycobalamin. Ib yam li ntawd, deoxyadenosine (5'-deoxyadenosyl), methyl (-CH3), cyanide (-CN) thiab cobalt ions txuas nrog los tsim adenosine cobalt. Amine (deoxyadenosylcobalamin), methylcobalamin (methylcobalamin) thiab cyanocobalamin (cyanocobalamin). Hauv xwm, daim ntawv kawg ntawm vitamin B12 biosynthesised los ntawm cov kab mob me me yog adenosine cobalamine (coenzyme B12), methyl cobalamine thiab hydroxycobalamine. Txawm li cas los xij, vim tias lawv cov khoom tsis ruaj khov heev, sodium cyanide yog ntxiv dag zog rau hauv cov txheej txheem kev ntxuav kom hloov cov qauv ntuj ntawm vitamin B12 mus rau hauv cyanocobalamin ruaj khov dua.
Kev Ua Haujlwm ntawm Lub Cev
Txhim kho qhov kev siv folic acid, tsim meththionine (ua los ntawm cysteine ntau) thiab choline nrog folic acid, thiab tsim cyanocobalamin precursors xws li methyl coballamin thiab coenzyme B12 hauv cov txheej txheem ntawm kev tsim prine thiab pyrimidine, thiab koom nrog hauv cov txheej txheem methylation ntawm ntau cov tshuaj tseem ceeb. Thaum vitamin B12 tsis txaus, qhov kev ua haujlwm ntawm kev hloov pauv methyl pawg los ntawm methyl tetrahydrofolic acid raug txo qis, ua rau folic acid tsis siv tau, ua rau folic acid tsis txaus. Tswj cov metabolism thiab kev ua haujlwm ntawm cov hlab ntsha myelin sheath. Tsis muaj vitamin B12 tuaj yeem ua rau muaj kev puas siab puas ntsws, kev puas tsuaj ntawm tus txha caj qaum, thiab tshuaj lom neeg tuaj yeem ua rau muaj cov tsos mob ntawm lub hlwb loj heev. Vitamin B12 tsis txaus tuaj yeem ua rau mob hlwb peripheral. Cov tsos mob thaum ntxov ntawm vitamin B12 tsis txaus hauv cov menyuam yaus yog kev xav tsis zoo, kev hais lus qeeb, kev teb qeeb, thiab thaum kawg ua rau muaj ntshav tsis txaus. Txhawb kev loj hlob thiab kev loj hlob ntawm cov qe ntshav liab. Methylpropandiyl coenzyme A raug hloov mus ua succinoyl coenzyme A thiab koom nrog hauv lub voj voog tricarboxylic acid, uas succinyl coenzyme A muaj feem cuam tshuam nrog kev tsim cov heme. Vitamin B12 kuj koom nrog kev tsim cov deoxynucleic acid (DNA), kev ua kom cov rog, carbohydrates thiab protein, thiab ua rau cov synthesis ntawm nucleic acids thiab proteins ntau ntxiv.
