Formate and its role in amino acid metabolism.

PURPOSE OF REVIEW: The aim of this report is to examine critical relationships between amino acid and formate metabolism with particular reference to the production of formate, and to review novel functions of formate.

RECENT FINDINGS: In addition to well established mechanisms in one-carbon metabolism, formate may play an important role in early pregnancy by preventing the onset of neural tube defects in sensitive strains of mice, including mice with deficiencies in MTHFD1L, the glycine cleavage system and the mitochondrial folate transporter. Markedly elevated, circulating levels of formate are found in late pregnancy, including in cord blood, as well as elevated levels of amino acid precursors. These are consistent with specific roles for formate in late pregnancy. Serine metabolism may reduce NADP to NADPH and permit the use of NADPH in reductive reactions. Novel, noncanonical functions of formate include high rates of formate production from serine in cells and in cancers.

SUMMARY: Novel, noncanonical functions of formate continue to be discovered. Integrating their functions with well established elements of one-carbon metabolism remains an important future objective.