Regulation of adenosine-5′-phosphosulfate sulfotransferase activity by H2S in Lemna minor L.

When Lemna minor L. is transferred to an atmosphere with H2S, there is a rapid loss of extractable adenosine-5′-phosphosulfate sulfotransferase activity. The activity is restored within 24 h in an atmosphere without H2S. This restoration of activity is completely inhibited by cycloheximid but not by chloramphenicol. In vitro, S2- up to 5 mM and cysteine, methionine, and glutathione up to 50 mM do not inhibit the enzyme. The activities of ATP sulfurylase and O-acetyl-L-serine sulfhydrylase are not affected significantly by H2S. The physiological significance of the regulation of adenosine-5′-phosphosulfate sulfotransferase is discussed.