Analytical subcellular fractionation studies on rat liver and on isolated jejunal enterocytes with special reference to the separation of lysosomes, peroxisomes and mitochondria.

1. Enterocytes were isolated from rat jejunum and characterized morphologically. 2. Attempts to separate the enterocyte subcellular organelles, characterized by their marker enzymes, with isopycnic centrifugation were unsuccessful but good separation of peroxisomes, lysosomes and mitochondria was achieved by sedimentation through a shallow sucrose density gradient with a super-imposed inverse gradient of low-molecular-weight dextran. 3. The properties and enzyme activities of the principal subcellular organelles in rat liver cells and enterocytes were compared.