Changes in the blood of the rat induced by the monocarboxylic acid of cyanocobalamin obtained by fermentation (anti-vitamin B12).

MONOCARBOXYLIC acid derivatives of vitamin B12 obtained by mild acid hydrolysis are competitive B12 antagonists in Escherichia coli. The three isomeric monocarboxylic acids so obtained differ from one another in both their microbiological and haematological activities1–3.