(A) Effect of supplementary cofactors (CoA, NAD, and ATP) on valinomycin formation. −, no cofactor added, +, cofactors were supplemented with 0.1 mM. ++, cofactors were supplemented with 1 mM. (B) Effect of the mass ratio of two cell extracts (CE) on valinomycin production. Values show means with error bars representing standard deviations (S.D.) of at least three independent experiments.