The phage shock protein (psp) operon (pspABCDE) may play a significant role in the competition for survival under nutrient- or energy-limited conditions. PspE catalyzes the sulfur-transfer reaction from thiosulfate to cyanide, to form sulfite and thiocyanate. Also able to use dithiol (dithiothreitol) as an alternate sulfur acceptor. Also possesses a very low mercaptopyruvate sulfurtransferase activity. hydrogen cyanide + thiosulfate = 2 H(+) + sulfite + thiocyanate Inhibited by thiosulfate above 100 mM, particularly at low cyanide concentrations (<5 mM). Inhibited by sodium sulfate or sodium chloride at 0.25 M which gives around 50% inhibition of rhodanese activity. Addition of sodium phosphate at the same concentration results in about 65% inhibition. Sulfite strongly inhibits PspE activity (1 mM sodium sulfite resulted in more than 50% inhibition of rhodanese activity). Monomer. By heat, ethanol, osmotic shock and infection by filamentous bacteriophages. Expression is positively regulated by cyclic AMP-cAMP receptor protein (cAMP-CRP). Expressed at higher levels during growth on glycerol, acetate or proline as carbon source relative to expression during growth on glucose. Catalysis proceeds by a classical ping-pong bi-bi reaction mechanism, whereby a covalent enzyme-sulfur intermediate is formed on the active site cysteine.