Bile lysosomal enzymes: characteristics and pathological significance for various hepatobiliary disorders

Abstract

The activities of several glycosidases (beta-galactosidase, beta-glucosidase, N-acetyl-beta-glucosaminidase) were demonstrated in human bile. The enzyme activities are increased about 100 times after exclusion of bile salts and other small molecular compounds by Sephadex G-50 gel filtration. The use of 4-methylumbelliferyl derivatives as substrates was useful as measurement of the bile enzyme activities are not altered in the presence of bile pigments. Enzyme characteristics of bile glycosidases were determined: pH optimum and isoelectric point. The bile glycosidase activities were also measured in various hepatobiliary disorders (cholelithiasis, cancer of gallbladder, acute hepatitis, liver cirrhosis and fatty liver). The glycosidase activities in bile from patients with liver diseases, as well as with cholelithiasis, were generally decreased. Isoelectric focusing patterns of biliary glycosidases were similar for specimens from patients with hepatobiliary disorders as compared to normal.