title: The two human lactosylceramidases and their respective enzyme activity deficiency diseases: inhibition studies using p-nitrophenyl-beta-D-galactoside.
abstract: Total lactosyl ceramide beta-galactosidase (LC) activity from normal and pathologic human leukocytes and tissues was subdivided into LC I (EC 3.2.1.46) and LC II (EC 3.2.1.23) activity by means of specific inhibition of LC II with 5 mM p-nitrophenyl-beta-D-galactoside (Ki = 1.5 mM). In globoid-cell leudodystrophy, inhibition of total LC was nearly complete (only LC II is active), whereas in GM1-gangliosidosis Type 1, very little inhibition was found (only LC I is actict). Total LC activity was not significantly low in either of the diseases, which have different genetic origins. The ratio of LC I to LC II activity may display remarkable genetic variation in normal probands.
mesh_terms: D002648:Child; D002675:Child, Preschool; D005696:Galactosidases / Q000172:deficiency*; D005698:Galactosylceramidase / Q000097:blood / Q000172:deficiency*; D005733:Gangliosidoses / Q000201:enzymology; D006801:Humans; D007223:Infant; D007787:Lactose Intolerance; D007962:Leukocytes / Q000201:enzymology; D007965:Leukodystrophy, Globoid Cell / Q000201:enzymology; D001616:beta-Galactosidase / Q000097:blood
chemical_list: D005696:Galactosidases; D001616:beta-Galactosidase; D005698:Galactosylceramidase