The distribution of 10-formyltetrahydrofolate synthetase, which activates formate for use as a one-carbon donor in a variety of biosynthetic reactions, was determined for a variety of eubacteria. Organisms from several genera were found to lack detectable synthetase activity; however, all organisms tested were found to contain 5,10-methylenetetrahydrofolate dehydrogenase activity.

PURPOSE Aberrant DNA methylation occurs in a subset of colorectal cancers and is characterized by regional areas of hypermethylation at CpG islands. The aims of this study were firstly to evaluate the levels of folate intermediates (FIs) in tumors with aberrant DNA methylation and secondly to determine whether these levels are affected by polymorphisms in key genes involved in folate metabolism...

PURPOSE Fluorouracil (5-FU) is widely used in the treatment of colorectal cancer. Methylenetetrahydrofolate reductase (MTHFR) could play an important role in the action of 5-FU, an inhibitor of thymidylate synthetase, by converting 5,10-methylenetetrahydrofolate, a substrate of thymidylate synthetase, to 5-methyltetrahydrofolate. A polymorphism in MTHFR (677 C-->T; A222V) reduces enzyme activit...

BACKGROUND Assay of methylenetetrahydrofolate reductase (MTHFR), a key enzyme in homocysteine metabolism, is important for the study of severe and mild deficiency states. Because the conventional assay measures in the reverse direction, lacks sensitivity, and uses nonphysiologic substrates, the exact measurement and characterization of residual activity in easily accessible tissues have been di...