[Enzymes involved in the metabolism of flavin nucleotides in Streptomyces olivaceus].

The work was aimed at studying enzymes involved in the metabolism of flavin nucleotides, namely, riboflavin kinase (EC 2.7.1.26) and FAD pyrophosphorylase (EC 2.7.7.2), as well as flavin mononucleotide hydrolysis by acid phosphatase (EC 3.1.3.2) and alkaline phosphatase (EC 3.1.3.1) in Streptomyces olivaceus actively producing vitamin B12. No correlation could be established between changes in the activity of the above enzymes during the culture growth and the qualitative composition of flavins. The enzyme activity was assayed using, as an enzyme preparation, both intact cells and a cell-free extract obtained by disintegrating the mycelium with different techniques. The screening effect of phosphatases exerted when the activity of riboflavin kinase was assayed could be partly eliminated by adding sodium fluoride to the incubation medium. The localisation of the above enzymes in the cytoplasm is discussed.