title: beta-D-galactosidase activities in juvenile GM1-gangliosidosis.
abstract: beta-Galactosidase activity was investigated in one case of juvenile GM1-gangliosidosis. This patient exhibited normal activity of the neutral form of beta-galactosidase (measured as beta-glucosidase activity) and normal pH curve of residual acid beta-galactosidase activity in leucocytes and fibroblasts. A shift towards more neutral pH optimum was seen in the beta-galactosidase enzyme occurring in serum. The communication also presents a study of the relationship of the different beta-galactosidases in human liver using isolated urine oligosaccharide from this patient as a beta-galactoside substrate. The other natural beta-galactoside substrates used in this investigation were different oligosaccharides, one glycopeptide and ceramide-beta-galactosidase. The beta-galactosidase forms with acidic pH optimum towards synthetic substrate (A forms) exhibit activity towards the natural substrate (except ceramide-beta-galactoside). The "neutral" beta-galactosidase with broad substrate specificity (B form) which includes beta-glucosides had no activity towards the natural substrates used. It could also be shown that the activity towards ceramide-beta-galactoside was a third type of beta-galactosidase different from A and B forms.
mesh_terms: D000293:Adolescent; D002850:Chromatography, Gel; D002852:Chromatography, Ion Exchange; D002854:Chromatography, Paper; D005347:Fibroblasts / Q000201:enzymology; D005696:Galactosidases / Q000378:metabolism*; D005733:Gangliosidoses / Q000201:enzymology*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007962:Leukocytes / Q000201:enzymology; D008099:Liver / Q000201:enzymology; D001616:beta-Galactosidase / Q000097:blood / Q000378:metabolism*
chemical_list: D005696:Galactosidases; D001616:beta-Galactosidase