Cyanocobalamine vitamin

Cyanocobalamin (vitamin B12) Propionibacterium freudenreichii Propionibacterium shermanii Pseudomonas denitriTicans Treatment of pernicious anaemia... 

Microbiological assay should stress accuracy over precision. Standardization of an assay method should include comparisons with at least one other organism having a different nutritional pattern and specificity toward the compound being assayed. Such a comparison was made for cyanocobalamin (vitamin Bi2 ) content of human blood and serum, using four microorganisms differing in their cobamide requirements and metabolism (B9). 

The metabolism of cyanide has been studied in animals. The proposed metabolic pathways shown in Figure 2-3 are (1) the major pathway, conversion to thiocyanate by either rhodanese or 3-mercapto-pyruvate sulfur transferase (2) conversion to 2-aminothiazoline-4-carboxylic acid (Wood and Cooley 1956) (3) incorporation into a 1-carbon metabolic pool (Boxer and Richards 1952) or (4) combining with hydroxocobalamin to form cyanocobalamin (vitamin B12) (Ansell and Lewis 1970). Thiocyanate has been shown to account for 60-80% of an administered cyanide dose (Blakley and Coop 1949 Wood and Cooley 1956) while 2-aminothiazoline-4-carboxylic acid accounts for about 15% of the dose (Wood and Cooley 1956). The conversion of cyanide to thiocyanate was first demonstrated in 1894. Conversion of cyanide to thiocyanate is enhanced when cyanide poisoning is treated by intravenous administration of a sulfur donor (Smith 1996 Way 1984). The sulfur donor must have a sulfane sulfur, a sulfur bonded to another sulfur (e.g., sodium thiosulfate). During conversion by rhodanese, a sulfur atom is transferred from the donor to the enzyme, forming a persulfide intermediate. The persulfide sulfur is then transferred... 

The ability of cyanide to form complexes with some metallic ions such as cobalt is the basis for the reaction with hydroxocobalamin that yields cyanocobalamin. Cyanocobalamin (vitamin B12), which contains cyanide and cobalt, is essential for the health of mammalian organisms. 

Figure 15.3 Structural formula of deoxyadenosylcobalamin (coenzyme B, ). (a) A plan view of the corrin nucleus with substituents, (b) The position of the remaining two ligands of the cobalt atom. No attempt is made to show correct stereochemical relationships. Related compounds have different groups in place of the 5 -deoxyadenosyl group cyanocobalamin, (vitamin Bi2)-CN hydroxycobalamin, (vitamin Bi2)-0H methylcobalamin, (vitamin Bi2)-CH3.

Severe cyanocobalamin (vitamin B12) deficiency results in pernicious anemia that is characterized by megaloblastic anemia and neuropathies. The symptoms of this deficiency can be masked by high intake of folate. Vitamin B12 is recycled by an effective enterohep-atic circulation and thus has a very long half-hfe. Absorption of vitamin B12 from the gastrointestinal tract requires the presence of gastric intrinsic factor. This factor binds to the vitamin, forming a complex that... 

Vitamin B12 Vitamin B12 is an important cobalt complex. The vitamin was isolated from liver after it was found that eating large quantities of raw liver was an effective treatment for pernicious anaemia. The term vitamin B12, refers to cyanocobalamin. Vitamin B12 is a coenzyme, and serves as a... 

Vitamins cyanocobalamin = vitamin B,2 (Rhdne-Poulenc and Merck Co) vitamin A (Hoffinann-La Roche) ascorbic acid (BASF), riboflavin (Hoffinann-La-Roche, BASF, and Rh6ne-Poulenc/Archer-Daniels), and niacinamide (Lonza). 

Vinyl polymerization, 332 Vitamin Bi2. See Cyanocobalamin Vitamin E. See Tocopherol Vitamin K, 43... 

Cyanocobalamin (vitamin Bl2) Propionibacterium shermanii. Pseudomonas dentrificans Food and animal feed supplement... 

Cyanocobalamin (vitamin B12), a cobalt complex first isolated from liver but now produced commercially from microbiological culture, is needed to maintain normal synthesis of red blood cells in man and animals. Ruminants obtain cyanocobalamin from their symbiotic rumen flora while in other herbivores such as the... 

Figure 1 Schematic representation of the molecular structure, numbering of atoms, and designations of pyrrole rings of cobalamins. R = Me is methyl B12 R = Ado is adenosyl-cobalamin (coenzyme B12) X = CN is cyanocobalamin (vitamin B12). Five-membered rings are labeled A-D, and the amide side-chains are labeled a-g.

Vitamin B. (.W pyridoxine) Vitamin B See cyanocobalamin) Vitamin C (See ascorbic acid) Vitamin D (Ergocalciferol) Vitamin D5 (Chlolcalciferol)... 

Vitamin B,2 (cyanocobalamin) Vitamin C—large doses Precipitate B,2 deficiency... 

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