ABSTRACT
This chapter describes the behavior of all subcellular particles during differential centrifugation of an homogenate, the density gradient systems will address exclusively the purification of the larger organelles which are recovered in the nuclear, heavy mitochondrial and light mitochondrial pellets. Moreover, any protein in the soluble fraction, whether native or dissociated from the surface of an organelle during the homogenization procedure can be trapped adventitiously by vesicles formed during the process. To protect organelles from the potentially damaging effects of proteases, which may be released from lysosomes during homogenization, it is common to include a cocktail of protease inhibitors in the homogenization medium. The proper selection of the correct species of plant and the choice of tissue are important because of the presence in some plant tissues of high levels of oxalates, phenols and starch which are deleterious the recovery of functioning chloroplasts.
