AN IMPROVED REPRODUCIBLE METHOD OF PREPARING RAT LIVER PLASMA CELL MEMBRANES IN BUFFERED ISOTONIC SUCROSE

Improvements are described for a method of isolating rat liver plasma cell membranes from a liver homogenate prepared in a 0.25 M sucrose-0.5 mM CaCl2-5 mM Tris buffer (pH 7.4). This method, introduced by Takeuchi and Terayama5, is reproducible and the preparation contains no nuclei, 5% mitochondria and 9% microsomes, as determined enzymatically. No DNA and 31.6 μg RNA per mg plasma membrane protein were found. This amount is considerably less than has previously been reported. The yield is 0.4 mg plasma membrane protein per g wet weight liver for adult male or female rats. Rats 3-4 weeks old yield about 1 4- 1 3 This amount. A discussion of the impurities in the preparation is appended. A comparison with similar methods indicates that from the point of view of reproductibility and impurities, the preparation described is the best available presently for cell homogenates made in isotonic sucrose. © 1969.