Reversible enzymatic synthesis of flavin-adenine dinucleotide.

An enzyme has been partially purified from brewer's yeast which catalyzes the reversible reaction between riboflavin phosphate and adenosine triphosphate (ATP) on the one hand and flavin-adenine dinucleotide (FAD) and inorganic pyrophosphate on the other in the presence of magnesium ions. ATP could not be replaced by adenosine diphosphate or adenosine-5-phosphate, and in the reverse reaction, inorganic pyrophosphate could not be replaced by ortho- or metaphosphate. With riboflavin and ATP a slight amount of FAD formation was observed.