Studies on Lysosomes

Part IV. On the behavior of esterase during the preparation of lysosomes from hog-liver

Abstract

Change in esterase activity was investigated during the preparation of lysosomes from hog liver. Hog liver esterase was considered not to be existing in lysosomal granules, but in microsomal particles. Free esterase detected in the lysosomal fraction was, therefore, most likely derived from microsomal particles.
Esterase was gradually liberated out of microsomal particles as the procedure-homogenization, freezing-thawing, warming, or storage-went on. Some inactivation of esterase, by heat denaturation or by lysosomal cathepsin, was observed during the procedure. Under the condition of pH 7.0, the ratio of inactivation showed the maximum at around 59°C and gradually decreased toward 0°C or 80°C.