Formiminoglutamate

Formiminoglutamate, often abbreviated as FIGLU, is an intermediate compound in the metabolic pathway of histidine degradation. It is formed from the conversion of N5-formyltetrahydrofolate and glutamate. Specifically, formiminoglutamate is generated when the formimino group is transferred from N5-formyltetrahydrofolate to glutamate, catalyzed by the enzyme formiminotransferase.

Following its formation, formiminoglutamate undergoes further enzymatic processing. The formimino group is then transferred to tetrahydrofolate, regenerating N5-formyltetrahydrofolate and forming glutamate. This process is mediated by formiminoglutamase. The overall pathway plays a role in the synthesis of purines and thymidylate, essential components of DNA.

Elevated levels of formiminoglutamate in the urine can be indicative of a folate deficiency. This is because a lack of folate impairs the efficient recycling of tetrahydrofolate, leading to an accumulation of the intermediate. Therefore, FIGLU excretion is sometimes used as a biochemical marker for assessing folate status, particularly in clinical settings. Its presence signifies a disruption in the normal flow of histidine metabolism and folate utilization.