A simple and sensitive assay for GM1 ganglioside (GM1) β-galactosidase activity was devised by direct measurement of released d-galactose using high-performance liquid chromatography (HPLC). GM1 β-galactosidase activity in crude samples such as brain homogenates could be measured by this method. After incubation of brain homogenate for 1 h with GM1 at 37°C and pH 4.4 in the presence of sodium taurodeoxycholate, the reaction was terminated by heating at 100°C for 2 min and the supernatant from the centrifuged sample was analysed directly by HPLC. d-Galactose isolated by HPLC was converted into a fluorescent compound by a post-column reaction with arginine at 150°C and the fluorescence intensity at 430 nm was measured with excitation at 320 nm. By this method 10 pmol of d-galactose could be measured and the fluorescence intensity was linear up to 1 mmol of d-galactose. Using this method, the optimal conditions for the activity of this enzyme were re-examined. As an application, the enzyme activity in the brain of a patient with GM1 gangliosidosis was examined. This method can be applied to any natural substrates, glycolipids or glycoproteins, the terminal galactose of which is hydrolysed by this enzyme.
|Number of pages||8|
|Journal||Journal of Chromatography B: Biomedical Sciences and Applications|
|Publication status||Published - 1988|
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