Anti-pemicious anemia factor

Twenty-two years later the isolation of the anti-pernicious anemia factor" was announced independently by Smith (5) and Riches (6). Seven years of chemical studies identified 5,6-dimethylbenzimidazole (7), D-ribose (5) and amino-propanol (9) as components of the anti-pemicious anemia factor", but the tetrapyrroline ring structure containing Co(III) awaited the X-ray crystallographic data on the cyano-derivative by Hodgkin and White (10—15). Once the structure of the antipemicious anemia factor was determined it was called Vitamin B12 (cyanocobal-amin). The recommendations of a number of commissions forms the basis of the present system of nomenclature for this molecule and these are presented in Fig. 1. 

Fio. 7. Comparison of the effects of liver extract and red anti-pemicious anemia factors (vitamin Bi or vitamin Bi concentrates) based on the changes in the mean total scores for neurological defect (from Ungley, C. C. 1949b. Brain 72, 382-427). 

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