Polyamines effect on subcellular fractionation of rat liver homogenate

1) Spermidine and spermine added to the homogenizing medium are able to increase the sedimentation velocity of mitochondria, smooth microsomes, lysosomes, Golgi apparatus and plasma membranes. Spermine at 0.5 mM enhances the sedimentation and at 3 mM is able to sediment, at 600 g for 10 min, almost the totality of membranous components of the cell. 2) Smooth microsomes were used as a model to study the nature of spermine effect. The amount of spermine bound to 1 g of smooth microsomes would increase their density of about 0.02%. In the presence of 1 mM spermine the great majority of smooth microsomes are unable to pass through a 10 μ filter indicating an extensive aggregation of the particles. 3) Spermine induced aggregation of smooth microsomes can be reversed by either heparin or poly-D-glutamic acid.