Distribution of Isomeric Eicosadienoic Acid in Lipid Classes of Sea Urchin

Abstract

It has been reported, in the previous papers, that a positional isomer of eicosadienoic acid, an unusual fatty acid, can be detected in fairly large quantities in the lipids of all sea-urchin species examined.
This finding led the author to clarification of the distribution of the isomer in the lipid classes of a sea-urchin species, Strongylocentrotus pulcherrimus. The lipids from the gonads and the other viscera were analysed for their fatty acid components by GLC, after being fractionated into the main lipid classes by silicic acid column chromatography. The results obtained are as follows:
1) The isomer is widely distributed in all the lipid classes from both the gonads and the other viscera. Its percentages in the gonads and the other viscera ranged from 5.0 to 7.5%, and 5.4 to 8.3%, respectively.
2) Most of the isomer was present in only two classes, i.e., polar lipids and triglycerides, in the amount of about 95% of the total weight of the isomer in the whole visceral organs. Its quantity in the gonads amounted to about 70% of the total.