Quantitative Distribution of an Esterase Among Cytoplasmic Components of Mouse Liver Cells.

Abstract

The esterase in the cytoplasm of mouse liver cells was found to be localized predominantly in the microsome fraction which contained an average of 47% of the enzyme in the whole tissue and 63% of that in the entire cytoplasm. Other cell fractions, the nuclear material, the large cytoplasmic granules, and the supernate from the microsome separation contained an average of 17%, 17%, and 14%, respectively, of the enzyme in the whole tissue. Enzyme activity per fig of N was greatest in the microsomes which contained a concentration that was 4.2 times that of the whole tissue. In the other particulate fractions, the nuclear material, the large cytoplasmic granules, and the supernate from the microsome separation, the enzyme concentration was found to be 0.6, 1.6, and 0.3 times, respectively, that of the whole tissue. The “lipoprotein” fraction of the microsomes displayed about 3 times the enzyme concentration found in the “nu-eleoprotein” fraction. Summation of the enzyme content of the substituent fractions indicated no appreciable loss during the separation procedures.