Organelle isolation by magnetic immunoabsorption

Currently most organelle isolation procedures rely on physical parameters a nd centrifugation for separation. Here. we report the rapid and gentle isol ation of a variety of organelles by immunolabeling whole cell lysates with organelle-specific antibodies and streptavidin magnetic particles follow ed by separation in a magnetic field Using magnetic immunoabsorption, we have been able to specifically label mouse metaphase chromosomes mm a variety o f plant organelles, including: amyloplasts chloroplasts and nuclei from who le cell lysates of various plant tissues. We find that the distinct magneti c properties, surface characteristics and mean diameter-size ranges of diff erent particle preparations significantly influence their specific utility! for organelle isolations. By using an internal-field magnetic separation d evice,,we have developed a method for quantitative recovery of labeled orga nelles in microarrays and rested a variety of antibodies to chloroplast out er envelope proteins for their ability to immune-isolate chloroplasts.