Soluble guanylate cyclase in Saccharomyces cerevisiae

After removing nonspecific immunoreactivities from crude extract by immunoaffinity chromatography, an immunoreactive-band at 40kDa of soluble guanylate cyclase (SGC) from Saccharomyces cerevisiae was detected by Western blot using rabbit anti-beta 1 subunit of SGC. Cyclic GMP level and SGC activity was measured by ELISA. Immunoprecipitated yeast SGC was activated by sodium nitroprusside, whereas inhibited by 1H-(1,2,4)oxadiazolo(4,3-A)quinoxalin-1-one. Increased cyclic GMP level was also noted when intact yeast cells were incubated with s-nitrosoglutathione, a NO donor. The result implies that NO can be utilized intracellularly and extracellularly. Moreover, the presence of SGC suggests the significance of NO/cyclic GMP signaling in unicellular eukaryotes.