Polar lipids extraction from rat primary lysosomes and their possible role in regulating lysosomal hydrolases

The polar lipids in primary lysosomes prepared from rat liver were extracted and evaluated by qualitative and quantitative procedures. Phospholipid phosphorus ranges between 1.50 and 2.6 micrograms/mg protein and sulfolipids varied from 12 to 60 micrometer/mg protein. The TLD of the organic phase have nine lipid fractions. Glycolipids were also present: GM1, GM3 and GD1a gangliosides could be separated by TLC. Sialic acid was about 0.24 micrograms/mg protein. The cytochemical interest of these components lies not only in the chemical composition of lysosomal structures, but also in the regulatory mechanism due to some of them, such as sulfolipids, which are likely to be involved in inactivating lysosomal enzymes by cross-inhibition.