Histochemical Studies on the Cholesterol Esterase Activity

Regulation of neutral cholesterol esterase activity

The effect of phospholipids on cholesteryl ester hydrolysis by neutral cholesterol esterase in alveolar macrophages was studied. Among the phospholipids used as emulsifiers, those with a negative charge, such as phosphatidylserine, phosphatidic acid, phosphatidylinositol, and cardiolipin, gave a higher level of hydrolysis by neutral cholesterol esterase than other less negatively charged phosph...

Histochemical and biochemical studies on leukocyte alkaline phosphatase activity.

Studies on the Specificity of Choline Esterase

The present investigation was undertaken to determine the relation between the structure of various substrates and the action of serum choline esterase upon them. The comparison of activities with different esters should take into account two factors : the hydrolytic velocities compared should be linear functions of time, and these velocities should be independent of substrate concentration. Th...

Intestinal cholesterol esterase: intracellular enzyme

The location of cholesterol esterase in rabbit intestine was re-evaluated. In three different experiments that were designed to eliminate contaminating mucus and pancreatic enzymes from the lumen of the small intestine, it was observed that the activities of cholesterol esterase and amylase in intestinal cytosol and whole homogenate decreased in parallel fashion. After the mucus was carefully w...

Effect of atherosclerosis on lysosomal cholesterol esterase activity in rabbit aorta.

Radiolabeled cholesteryl oleate, when incorporated into phospholipid vesicles, was hydrolyzed at acid pH by an enzyme present in rabbit aortic homogenates. In contrast, cholesteryl oleate presented as an acetone dispersion was not effectively hydrolyzed at acid pH under identical conditions. Using the vesicle preparation as substrate, a sensitive assay system for the acid hydrolase was develope...