Incorporation of [1-14C] acetate into lipids of soybean cell suspensions

Suspension cultures of soybean cells incorporated [1-¹⁴C] acetate very rapidly into the fatty acid moieties of phospholipids and glycolipids when incubated at 26 C for up to 22 hr. The most rapidly labeled lipid was 3-sn-phosphatidylcholine, which contained 58% of the total fatty acid radioactivity after 16 min; more than 75% of this label was found to be in the oleic acid of the phosphatidylcholine. After longer periods of incubation, the proportion of¹⁴C label decreased exponentially in phosphatidylcholine and increased markedly in an unidentified phospholipid (tentatively,bis-phosphatidic acid), di- and triacylglycerols, and glycolipids. The proportion of radioactivity in oleic acid also decreased exponentially, accompanied by increases in linoleic acid first and then in linolenic acid. Most of the labeled linolenic acid at 22 hr was found in the unidentified phospholipid, di- and triacylglycerols, and the glycolipid fraction. Contribution no. 537, Ottawa Research Station, Agriculture Canada. A preliminary report was presented at the 20th International Conference on the Biochemistry of Lipids at Aberdeen, Scotland, September 1977.