5-methyltetrahydrofolic acid 5-methyltetrahydrofolate(2-) A dicarboxylic acid dianion resulting from the deprotonation of the two carboxy groups of 5-methyltetrahydrofolic acid; major species at pH 7.3. 5-methyltetrahydrofolate dicarboxylic acid dianion 5,6,7,8-tetrahydrofolate(2-)