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It can bind two different forms of the cobalamin cofactor, with cobalt bonded either to a methyl group (methylcobalamin) or to 5'-deoxyadenosine (adenosylcobalamin). Cobalamin-binding domains are mainly found in two families of enzymes present in animals and prokaryotes, which perform distinct kinds of reactions at the cobalt-carbon bond .
Animals, including humans, can convert cyanocobalamin to any one of the active vitamin B 12 compounds. [21] Cyanocobalamin is one of the most widely manufactured vitamers in the vitamin B 12 family (the family of chemicals that function as B 12 when put into the body), because cyanocobalamin is the most air-stable of the B 12 forms. [22]
Cyanocobalamin is the most common form used in dietary supplements and food fortification because cyanide stabilizes the molecule against degradation. Methylcobalamin is also offered as a dietary supplement. [12] There is no advantage to the use of adenosylcobalamin or methylcobalamin forms for the treatment of vitamin B 12 deficiency. [20] [21 ...
Methylcobalamin (mecobalamin, MeCbl, or MeB 12) is a cobalamin, a form of vitamin B 12. It differs from cyanocobalamin in that the cyano group at the cobalt is replaced with a methyl group . [ 1 ] Methylcobalamin features an octahedral cobalt(III) centre and can be obtained as bright red crystals. [ 2 ]
In methylcobalamin the ligand is a methyl group, which is electrophilic. in vitamin B12, the alkyl ligand is an adenosyl group. Related to vitamin B12 are cobalt porphyrins, dimethylglyoximates, and related complexes of Schiff base ligands. These synthetic compounds also form alkyl derivatives that undergo diverse reactions reminiscent of the ...
Its active form is a coenzyme called thiamine pyrophosphate (TPP), which takes part in the conversion of pyruvate to acetyl coenzyme A in metabolism. [11] Vitamin B 2: Riboflavin: Riboflavin is involved in release of energy in the electron transport chain, the citric acid cycle, as well as the catabolism of fatty acids (beta oxidation). [12 ...
Cyanocobalamin is usually converted to hydroxocobalamin in the serum, whereas hydroxocobalamin is converted to either methylcobalamin or adenosylcobalamin. Cobalamins circulate bound to serum proteins called transcobalamins (TC) and haptocorrins. Hydroxocobalamin has a higher affinity to the TC II transport protein than cyanocobalamin, or ...
Vitamin B 12 deficiency; Other names: Hypocobalaminemia, cobalamin deficiency: Image of the cervical spinal cord in vitamin B 12 deficiency showing subacute combined degeneration. . (A) The midsagittal T2 weighted image shows linear hyperintensity in the posterior portion of the cervical tract of the spinal cord (black arrow