RAPID AND LARGE-SCALE ISOLATION OF MICROSOMAL FRACTION OF MOUSE-LIVERBY LYOPHILIZATION AND LOW-SPEED CENTRIFUGATION

We could prepare the microsomal fraction of mouse liver. without using an ultracentrifuge but with a low speed centrifuge. The procedure inc ludes 1) lyophilization of post-mitochondrial fraction (9,000 x g supe rnatant) of mouse liver, 2) powdering of the lyophilized sample, 3) th e addition of 1.15 per cent potassium chloride solution or distilled w ater, which afforded microsomal aggregates, 4) sedimentation of micros omal fraction by low-speed centrifugation (20,000 x g, 20 min). The se dimented microsomal fraction showed normal contents of cytochrome P-45 0 and cytochrome b(5), and gave a normal pattern on SDS polyacrylamide gel electrophoresis and normal electron microscopic feature. This met hod should be convenient for rapid and large-scale preparation of micr osomes, especially for the preparation of cytochrome b(5) and cytochro me P-450.