Studies on Sulfate Utilization by Chlorella pyrenoidosa using Sulfate-S35; the Occurrence of S-Adenosyl Methionine.

Abstract

Sulfate-S35 is taken up rapidly by C. pyrenoidosa and is converted to reduced compounds within the cell. One of the compounds formed from S35O4[long dash]shows the properties of S-adenosyl methionine. Preliminary evidence is also presented for the formation of "active" sulfate. Techniques were developed to stabilize and control the process of sulfate reduction in Chlorella bv using iodoacetamide as an inhibitor. The effects of concentration and time of addition of iodoacetamide on the reduction process are described. Iodoacetamide serves to reduce the number of spurious compounds produced during extraction and separation of the labeled products and also increases the incorporation of label into the soluble fraction at the expense of the insolubles. By utilizing iodoacetamide and relatively mild extraction techniques, reproducible chromatograms have been obtained of the soluble fraction. Most of the compounds formed are still unidentified, some may be conjugates of acetamide with sulfhydryl compounds. Some speculations on the role of compounds of adenosine and sulfur in sulfate reduction are also presented.