Interrelationships of vitamin B12 and folate in man

The relationship between cobalamin and folate coenzymes in hemopoiesis appears to be the result of some role of cobalamins in the utilization of folates. The effects of cobalamin deficiency on folate metabolism are discussed in the context of those hypotheses which are best able to explain the observed data. Although unproved, the most satisfactory hypothesis is that, in cobalamin deficiency, folates accumulate as methyltetrahydrofolate, and thus deplete the other folate coenzymes on which purine biosynthesis, thymidylate biosynthesis and histidine catabolism depend