10-Formyltetrahydrofolate

Functions

Two equivalents of 10-CHO-THF are required in purine biosynthesis through the pentose phosphate pathway, where 10-CHO-THF is a substrate for phosphoribosylaminoimidazolecarboxamide formyltransferase.

10-CHO-THF is required for the formylation of methionyl-tRNA formyltransferase to give fMet-tRNA.

Formation from methenyltetrahydrofolate

10-CHO-THF is produced from methylenetetrahydrofolate (CH2H4F) via a two step process. The first step generates 5,10-methenyltetrahydrofolate:

:CH2H4F + NAD+ \rightleftharpoons CH2H2F + NADH + H+ In the second step 5,10-methenyltetrahydrofolate undergoes hydrolysis: :CH2H2F + H2O \rightleftharpoons CHO-H4F + The latter is equivalently written: :5,10-methenyltetrahydrofolate + H2O \rightleftharpoons 10-formyltetrahydrofolate

10-CHO-THF is also produced by the reaction :ATP + formate + tetrahydrofolate \rightleftharpoons ADP + phosphate + 10-formyltetrahydrofolate This reaction is catalyzed by formate-tetrahydrofolate ligase.

It can be converted back into tetrahydrofolate (THF) by formyltetrahydrofolate dehydrogenase or THF and formate by formyltetrahydrofolate deformylase.

References

References

1. (2016). "Fundamentals of Biochemistry: Life at the Molecular Level". Wiley.
2. (1998). "Methenyltetrahydrofolate Cyclohydrolase Is Rate Limiting for the Enzymatic Conversion of 10-Formyltetrahydrofolate to 5,10-Methylenetetrahydrofolate in Bifunctional Dehydrogenase-Cyclohydrolase Enzymes". Biochemistry.