Secondary alkylsulfatases (S-1 and S-2) were detected inPseudomonasC12B cultured in minimal media lacking alkylsulfates. The synthesis of these enzymes was not repressed by SO42−andL-cysteine or derepressed byL-methionine. Growth on 4% sodium citrate caused a 98% loss in the secondary alkylsulfatase activity of cells and 9% of this activity was detected in the culture medium. Citrate (20 mM) inhibited the activity of cell extracts (18%) but the inhibition was reversible by dialysis. The primary alkylsulfatase content of cells was not diminished by growth on citrate. The MgCl2concentration of the medium also influenced the cellular levels of secondary alkylsulfatase. Bacteria grown on MgCl2(0.05 mM – 40 mM) exhibited progressively increasing activity while the converse distribution was observed for activity present in the medium after growth at each MgCl2concentration. Both primary and secondary alkylsulfatases were released when cells were either subjected to osmotic shock or treated for cell wall removal. Cells washed with 0.085 M sodium citrate – 10 mM Tris – 20% sucrose released roughly 87% of both enzymes and MgCh (0.04 M) inhibited the release of primary alkylsulfatase by 11% and secondary alkylsulfatase by 50%. It is suggested that citrate chelates divalent cations necessary for the attachment of secondary alkylsulfatase at the cell periphery.