Active form of folic acid
Active form of Folic acid is Tetrahydrofolate. A. The folic acid is first reduced to 7,8-dihydrofolic acid and fuher reduced to 5,6,7,8-tetrahydrofolic acid (THFA) . Both reactions are catalyzed by NADPH dependent folate reductase. B. The THFA is the carrier of one-carbon groups. One carbon compound is an organic molecule that contains only a single carbon atom. The following groups are one carbon compounds: i.Formyl (-CHO) ii.Formimino (-CH=NH) iii.Methenyl (-CH=) iv.Methylene (-CH2-) v.Hydroxymethyl (-CH2OH) vi. Methyl (-CH3) C.These one carbon compounds are attached either to the 5th or to the 10th or to both 5 and 10 nitrogen atoms of THFA. The one-carbon metabolism and their interconversions D.Methyl group in N5-methyl THFA is used for synthesis of active methionine, which takes pa in transmethylation reactions. Such transmethylation reactions are required for synthesis of choline, epinephrine, creatine, etc. Reference: Vasudevan Textbook of Biochemistry pg no. 401
Dihydrofolate
Folinic acid
Tetrahydrofolate
Methylated folic acid
vitamins