CYANOCOBALAMIN (VITAMIN B12)
Chimiro uye Hunhu
Chigadzirwa ichi ipfu rakatsvuka rekristaro kana rekristaro, harinhuwi, harina kunaka uye rine hunhu hwakasimba hwekunyorova. Rinonyungudika zvishoma mumvura kana ethanol, harinyungudike muchloroform kana ether. Rinodzivirira kupisa, asi rinogona kusashanda kana rikasangana nezvinhu zvinooxidating kana kuderedza oxidation (senge vitamin C kana hydrogen peroxide, nezvimwewo), heavy metal salts uye strong acids uye strong alkalis.
Maumbirwo emakemikari
Vhitamini B12 imusanganiswa we equioctaphedral une ma ioni e cobalt. Chimiro chayo chepakati idenderedzwa rakatsetseka re corrin rakaumbwa nema pyrroles mana akabatana. Mamorekuru evhitamini B12 akaumbwa nezvikamu zvitatu: gourin ring yakasanganiswa nemaatomu mana e N uye ma ioni e cobalt ari pakati; 5,6-dimethylbenzimidazole (5,6-dimethylbenzimidazole, DMBI) yakabatana nemaatomu e N-7 uye ma ioni e cobalt semamorekuru evhitamini B 12 ema ligands e low-level (α) ligands. Pamusoro pezvo, DMBI yakabatanawo ne aminopropanol kuburikidza nemapoka e phosphate, uye aminopropanol yakabatana pamwe chete ne propionic acid side chain pa pyrrole D; adenosyl group kana methyl group. Yakabatana nema ioni e cobalt kuti igadzire upper (β) ligand yemamorekuru evhitamini B12. Mhando dzakasiyana dzezvinhu zvevhitamini B12 dzinoumbwa kana boka re chemical book rakasiyana ne upper chemical book riri pa axis ye goline ring. Boka rehydroxyl (-OH) rakabatana necobalt ion iri mugluline ring kuti igadzire hydroxycobalamin. Saizvozvowo, deoxyadenosine (5'-deoxyadenosyl), methyl (-CH3), cyanide (-CN) uye cobalt ions zvakabatana kuti zvigadzire adenosine cobalt zvakateerana. Amine (deoxyadenosylcobalamin), methylcobalamin (methylcobalamin) uye cyanocobalamin (cyanocobalamin). Muzvisikwa, fomu yekupedzisira yevhitamini B12 inogadzirwa netupukanana iadenosine cobalamine (coenzyme B12), methyl cobalamine uye hydroxycobalamine. Zvisinei, nekuda kwekuti hunhu hwavo hahuna kugadzikana zvakanyanya, sodium cyanide inowedzerwa nenzira yekugadzira muindasitiri yekuchenesa kuti ishandure fomu yechisikigo yevhitamini B12 kuita cyanocobalamin yakagadzikana zvakanyanya.
Basa remuviri
Vandudza mwero wekushandiswa kwefolic acid, kugadzira meththionine (inogadzirwa kubva kucysteineine yakakwira) uye choline nefolic acid, uye kugadzira cyanocobalamin precursors dzakadai semethyl coballamin necoenzyme B12 mukugadzira prine nepyrimidine, uye kutora chikamu mukuita kwemethylation yemakemikari akawanda akakosha. Kana vhitamini B12 isina kukwana, basa rekutamisa mapoka emethyl kubva kumethyl tetrahydrofolic acid rinoderera, zvichiita kuti folic acid ive fomu isingashandiswi, zvichikonzera kushomeka kwefolic acid. Chengetedza metabolism uye mashandiro e nerve myelin sheath. Kushaikwa kwevhitamini B12 kunogona kukonzera matambudziko etsinga, kuora kwemusana, uye bhuku remakemikari rinogona kukonzera zviratidzo zvakakomba zvepfungwa. Kushaikwa kwevhitamini B12 kunogona kutungamira ku peripheral neuritis. Zviratidzo zvekutanga zvekushaikwa kwevhitamini B12 muvana ipfungwa dzisina kujairika, kutaura zvishoma nezvishoma, kunonoka kuita, uye pakupedzisira zvinotungamira ku anemia. Kukurudzira kukura nekukura kwemasero matsvuku eropa. Methylpropandiyl coenzyme A inoshandurwa kuita succinoyl coenzyme A uye inobata chikamu mu tricarboxylic acid cycle, umo succinyl coenzyme A inobatana nekugadzirwa kwe heme. Vhitamini B12 inobatawo chikamu mukugadzirwa kwe deoxynucleic acid (DNA), metabolism yemafuta, makabhohaidhiretsi neprotein, uye inowedzera kugadzirwa kwe nucleic acids nemapuroteni.
