CYANOCOBALAMIN (FITAAMIIN B12)
Qaabka iyo Sifooyinka
Badeecadani waa budo kiristaal casaan ah ama kiristaal ah, aan ur lahayn, dhadhan lahayn waxayna leedahay sifooyin xoog leh oo keena qoyaan. Waxaa si yar ugu milmi kara biyaha ama ethanol, kuma milmi karo kloroform ama ether. Kulaylku wuu u adkaystaa, laakiin waxtar ma yeelan karto marka la kulmo walxaha oksaydhka ama yareeya (sida fiitamiin C ama hydrogen peroxide, iwm.), cusbada birta culus iyo asiidhyada xooggan iyo alkaliyada xooggan.
Qaab-dhismeedka Kiimikada
Faytamiin B12 waa isku-dhis equioctaphedral ah oo ka kooban aayoon kobalt. Qaab-dhismeedkiisa dhexe waa giraan siman oo corrin ah oo ka kooban afar pyrroles oo isku xiran. Molecules-ka fitamiin B12 waxay ka kooban yihiin 3 qaybood: giraan gourin ah oo ay ku jiraan afar aayoon N iyo aayoon kobalt dhexe; 5,6-dimethylbenzimidazole (5,6-dimethylbenzimidazole, DMBI) oo ku xiran aayoonka N-7 iyo aayoon kobalt sida molecules-ka fitamiin B 12 ee ligands-ka heerka hoose (α). Intaa waxaa dheer, DMBI waxay sidoo kale ku xiran tahay aminopropanol iyada oo loo marayo kooxaha fosfate, aminopropanol-na si isku xiran ayay ugu xiran tahay silsiladda dhinaca ee aashitada propionic ee pyrrole D; kooxda adenosyl ama kooxda methyl. Waxay ku xiran tahay aayoon kobalt si ay u sameyso ligand-ka sare (β) ee molecules-ka fitamiin B12. Noocyada kala duwan ee walxaha fitamiin B12 ayaa la sameeyaa marka kooxda buugga kiimikada ay ka duwan tahay buugga kiimikada sare ee ku yaal dhidibka giraanta goline. Kooxda hydroxyl (-OH) waxay ku xiran tahay ion-ka kobalt ee ku jira giraanta gluline si ay u sameyso hydroxycobalamin. Sidoo kale, deoxyadenosine (5'-deoxyadenosyl), methyl (-CH3), cyanide (-CN) iyo ion-ka kobalt ayaa ku xiran si ay u soo saaraan adenosine cobalt siday u kala horreeyaan. Amine (deoxyadenosylcobalamin), methylcobalamin (methylcobalamin) iyo cyanocobalamin (cyanocobalamin). Dabeecadda, qaabka ugu dambeeya ee fitamiin B12 ee ay nooleeyaan noolaha yaryar waa adenosine cobalamine (coenzyme B12), methyl cobalamine iyo hydroxycobalamine. Si kastaba ha ahaatee, sababtoo ah sifooyinkoodu ma aha kuwo aad u deggan, sodium cyanide si macmal ah ayaa loogu daraa habka nadiifinta warshadaha si loogu beddelo qaabka dabiiciga ah ee fitamiin B12 cyanocobalamin oo deggan.
Shaqada Jirka
Hagaaji heerka isticmaalka folic acid, isku-darka meththionine (laga sameeyay cysteine-ka sare) iyo choline oo leh folic acid, iyo isku-darka cyanocobalamin precursors sida methyl coballamin iyo coenzyme B12 habka soo saarista prine iyo pyrimidine, oo ka qaybqaado habka methylation-ka ee iskudhisyo badan oo muhiim ah. Marka fitamiin B12 uu yar yahay, dhaqdhaqaaqa wareejinta kooxaha methyl ee ka imanaya methyl tetrahydrofolic acid waa la dhimaa, taasoo ka dhigaysa folic acid qaab aan la isticmaali karin, taasoo keenta yaraanta folic acid. Joogteynta dheef-shiid kiimikaadka iyo shaqada xuubka myelin-ka neerfaha. La'aanta fiitamiin B12 waxay sababi kartaa khalkhal neerfaha, burburka laf-dhabarta, iyo buugga kiimikada waxay sababi kartaa calaamado maskaxeed oo halis ah. La'aanta fiitamiin B12 waxay horseedi kartaa neuritis-ka durugsan. Calaamadaha hore ee yaraanta fitamiin B12 ee carruurta waa niyadda aan caadiga ahayn, muujinta gaabiska ah, falcelin gaabis ah, ugu dambayntiina waxay horseeddaa dhiig-yaraan. Kor u qaad horumarka iyo bislaanshaha unugyada dhiigga cas. Methylpropandiyl coenzyme A waxaa loo beddelaa succinoyl coenzyme A waxayna ka qaybgashaa wareegga tricarboxylic acid, kaas oo succinyl coenzyme A uu la xiriiro isku-darka heme. Faytamiin B12 sidoo kale wuxuu ka qaybqaataa isku-darka deoxynucleic acid (DNA), dheef-shiid kiimikaadka dufanka, karbohaydraytyada iyo borotiinka, wuxuuna kordhiyaa isku-darka asiidhyada nucleic iyo borotiinnada.
