fumaric acid

An intermediate in the TCA cycle formed by the dehydrogenation of succinic acid with the concomitant production of FADH₂ from FAD. It has the formula COOH(CH)₂COOH. In the next step of the cycle fumaric acid reacts with water to form malic acid. Fumaric acid is also involved in amino acid metabolism. It is formed by the degradation of phenylalanine and tyrosine. In amino acid synthesis it is thought ammonia may react with fumaric acid to form aspartic acid.