Definition: A cobalt-containing coordination compound produced by intestinal micro-organisms and found also in soil and water. Higher plants do not concentrate vitamin B 12 from the soil and so are a poor source of the substance as compared with animal tissues. INTRINSIC FACTOR is important for the assimilation of vitamin B 12.
Vitamin B12, mixt. with (T-4)-bis(1,2,3,6-tetrahydro-2,6-dioxo-4-pyrimidinecarboxylato-N3,O4)magnesium, 2-hydroxy-N,N,N-trimethylethanaminium salt with 1,2,3,6-tetrahydro-2,6-dioxo-4-pyrimidinecarboxylic acid (1:1) and 3,7,12-Trioxocholanic acid