Inhibition of enzyme induction in Pseudomonas aeruginosa by exogenous nucleotides.

Alkylsufatase induction in resting cell suspensions of P. aeruginosa was inhibited by exogenously supplied adenosine or by ATP (2mM). Adenine phosphate had no effect while AMP or ADP caused a slight stimulation of induction. The inhibitory effect of ATP required the presence of added Mg2+, was not reversed by cyclic-AMP (2mM), and was independent of the nature of the inducer. Of a number of other nucleoside triphosphates tested, only UTP (2mM) acted as an inhibitor of induction. These nucleotides at external concentrations of 6mM also inhibited alkysulfatase induction in actively growing cells.