Folinic acid is:: (A) 5-formyl tetrahydrofolate, (B) 5-formyl dihydrofolate, (C) N5, N10-methylene tetrahydrofolate, (D) N5, N10-methylene dihydrofolate
Answer is A. * Folinic acid is 5-formyltetrahydrofolate. It is also known as leucovorin and citrovorum factor. * Folinic acid can be directly conveed to N5, N10-methylene tetrahydrofolate. Extra:-When methotrexate is used for chemotherapy, normal cells are also affected. * Folinic acid is administered to rescue the normal cells from the toxic effect of methotrexate.