at the concentrations of folate commonly used in the assay of folate vitamin in foods the response of l. casei to folic acid , ( pteroylglutamic acid ) and 5-formyl-tetrahydrofolic acid was similar , but 5-methyl-tetrahydrofolic acid gave as little as half the response of folic acid .
C0023413
5-formyl-tetrahydrofolic acid
C0016410
folic acid