Receptor-mediated endocytosis of enterokinase by rat liver. Preliminary characterisation of low-density endosomes

Isolation of the major subcellular organelles from mouse liver using Nycodenz gradients without the use of an ultracentrifuge

Commonly, subcellular organelles such as nuclei, mitochondria, lysosomes, and Golgi membranes are isolated first by differential centrifugation in low-speed or high-speed centrifuges and then purified by gradient centrifugation in ultracentrifuges. We have prepared these organelles using a new high-speed centrifuge (28,000 rpm max) which allows the generation of higher radial centrifugal forces (rcfs) than are available in standard machines. We have shown that most subcellular organelles can be purified by using low-viscosity Nycodenz gradients at rcfs lower than those normally used in ultracentrifuges, without increasing the time of centrifugation. Use of Nycodenz also allows rapid harvesting of material from gradients and we have adapted a number of enzyme assays to facilitate gradient analysis.