Regulation of primary alkylsulfatase induction in Pseudomonas C12B: concentration-dependent stimulation-inhibition by exogenous UTP and sodium acetate and inhibition by 1-hexanol.

Pseudomonas C12B, an isolate from detergent-enriched soil, synthesized primary alkylsulfatase in response to sodium hexan-1-yl sulfate as the inducer. The induction of this enzyme was inhibited by exogenous 1 mM UTP but not by ATP or other nucleoside triphosphates. The uridine nucleotide was about 10-fold more effective than other uracil-related effectors and the ability of the nucleotide (0.1-1.0 mM) to inhibit induction was dependent upon the presence of added Mg2+. At concentrations less than 0.1 mM, UTP stimulated induction and the extent of this effect was also Mg2+ dependent. Marked stimulation of induction also occurred in response to low (less than or equal to 2.5 mM) concentrations of acetate, citrate, and succinate. However, only acetate inhibited induction (by 64%) at higher (20 mM) concentrations. 1-Hexanol was a more effective inhibitor. An 80% reduction in activity was recorded after exposure of cells to 5 mM 1-hexanol. At this concentration, 2-hexanol was without effect and 3-hexanol inhibited induction by 35%. Simultaneous exposure of the cells to 2,4-dinitrophenol failed to reverse hexanol- or acetate-mediated inhibition. It is suggested that 1-hexanol per se regulates alkylsylfatase induction and immediate product inhibition was proposed as a term to describe this type of inhibition.