Sequential preparation of rat liver microsomal and Golgi membranes.

A new procedure for the preparation of microsomes, microsomal subfractions and Golgi membranes from the same piece of rat liver has been developed. The smallest amount of liver with which the preparation can be performed is about 1 g (wet weight). 35% of the total activity of marker enzymes for the endoplasmic reticulum was recovered in the microsomal fraction. This recovery is approximately the same as that obtained in our laboratories using other procedures. Golgi membranes, mitochondria, lysosomes and plasma membranes represent less than 13% of the microsomal protein as calculated on the basis of marker enzymes. Golgi membranes must be prepared in two steps to achieve a reasonable recovery and thus a representative sample containing both very low density lipoprotein-rich Golgi vesicles and the heavier cisternal elements. The recovery of UDP-galactosyltransferase activity in the Golgi fraction from the livers of alcohol-treated animals is around 30% of the total activity in the total particulate fraction.