EFFECT OF SULFHYDRYL-REAGENTS ON POTASSIUM EFFLUX FROM PSEUDOMONAS-AERUGINOSA CAUSED BY METAL-SALTS

N-Ethyl maleimide (NEM), cyanogen iodide (ICN) and azobenzene sulfenyl bromide (Azo) increase K+ efflux from [P. aeruginosa] cells suspended in 1.2 .times. 10-4 M NaOH, pH 8.5. After 40 min incubation the pH of control cells was 7.4, with NEM, 6.8, and with ICN or Azo 8.1. In maximal concentrations, the effect of NEM is additive with ICN or Azo. The effect of ICN with Azo is less than additive. Thus NEM and ICN or Azo are reacting with different sites, and ICN and Azo are reacting in part with the same site. Several metal salts increase the K+ efflux. The effect of Cu is inhibited by very low concentrations of all 3 compounds. The effects of Ag and Hg are not inhibited by NEM but are by very low concentrations of ICN or Azo. The effect of Ca or (Ba) is inhibited by NEM but not significantly by ICN or Azo. The effect of U is not inhibited by NEM but is by relatively large concentrations of ICN or Azo. The effects of the other ions are inhibited to varying extents by all 3 compounds. The effects of most of the salts are less inhibited when NEM is added after than before them. Except for Ag, the order of addition of the salts and ICN or Azo is without effect.