510-methenyltetrahydrofolate

5,10-meth·e·nyl·tet·ra·hy·dro·fo·late (meth″ə-nəl-tetґrə-hi″dro-foґlāt) a substituted derivative of tetrahydrofolate, carrying a methylidyne group; it is formed in histidine degradation and in the interconversion of various folates, linking the flow of activated one-carbon units from serine and thymidylate synthesis with purine synthesis and the liver enzyme system for discarding excess single carbons.