Utilization of One-Carbon Substituted Folates

Two reactions tue of specitd interest thymidylate synthetase (Section 10.3.3) and remethylation of homocysteine to methionine (Section 10.3.4). This latter reaction is centred to the control of the metabolism of one-carbon compounds and folate. 

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Figure 45-16. Sources and utilization of one-carbon substituted folates.

Folic acid plays the central role in one-carbon metabolism and is directly or indirectly involved in the biosynthesis of nucleic acid bases and amino acids. In plants and microbes, the various folate derivatives involved in one-carbon metabolism originate from dihydropterin derivatives, via the enzymes 7,8-dihydropteroate and dihydrofolate synthase (Figure 5.18). 7,8-Dihydrofolate then undergoes reduction to 5,6,7,8-tetra-hydrofolate (THF), which can become substituted with formyl, methylene, or methyl groups for utilization in one-carbon donor reactions. ... 

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