Occurrence of Flavokinase Activity in Plants

Abstract

RIBOFLAVIN functions biologically as either flavin mononucleotide or flavin-adenine-dinucleotide, which constitute the prosthetic group of a variety of enzymes¹. A study of pathways through which these nucleotides themselves are synthesized from the free vitamin would be valuable. The only reports in the literature regarding the enzymatic synthesis of flavin mononucleotide pertain to the study of the enzyme from baker's yeast² and a riboflavin-excreting mutant yeast BY2 ³. On the basis of the specificity and stoichiometry of the reaction, the enzyme was designated ‘flavokinase’. In this communication, the occurrence of the enzyme in plants is reported for the first time.