Characterization of neutral and acid ester hydrolase in Wolman's disease

Wolman's disease is characterized by diffuse cellular accumulation of cholesteryl ester and triacylglycerol, steatorrhea, and death in infancy. Although lysosomal acid ester hydrolase has been reported to be absent in tissues from affected infants, full evaluation of the intracellular ester hydrolases in hepatic and nonhepatic tissues has not been performed previously. Studies on ester hydrolase activity in human liver and skin fibroblasts have permitted the following conclusions. (1) The ester hydrolase activity for cholesteryl oleate and triolein are parallel in human liver and skin fibroblasts. (2) There is a significant loss of activity for both of these substrates at pH 4 in both liver and skin fibroblasts in a subject with Wolman's disease. (3) At pH 7, however, ester hydrolase activity for both substrates in both liver and skin fibroblast preparations from a patient with Wolman's disease is preserved. (4) The patient's mother, an obligate heterozygote, does not demonstrate any loss of activity for either substrate at pH 4. THese data are consistent with the concept that acid and neutral ester hydrolases are different enzymes.