A Fluorescence-Based High-Performance Liquid Chromatographic Assay to Determine Acid Ceramidase Activity

Acid ceramidase (N-acylsphingosine amidohydrolase) is the lysosomal enzyme required to hydrolyze the N-acyl linkage between the fatty acid and sphingosine moieties in ceramide. A deficiency of acid ceramidase activity results in the lipid storage disorder, Farber disease. This study reports a new as...

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Bibliographic Details
Published in:Analytical biochemistry 1999-10, Vol.274 (2), p.264-269
Main Authors: He, Xingxuan, Li, Chi-Ming, Park, Jae-Ho, Dagan, Arie, Gatt, Shimon, Schuchman, Edward H.
Format: Article
Language:English
Subjects:
Acid Ceramidase
Amidohydrolases - analysis
Animals
Cell Line
Ceramidases
Chromatography, High Pressure Liquid - methods
Farber disease
Fibroblasts - enzymology
Fluorescence
fluorescent ceramide
high-performance liquid chromatography
Humans
Lysosomal Storage Diseases - enzymology
Mice
Skin - enzymology
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Summary:Acid ceramidase (N-acylsphingosine amidohydrolase) is the lysosomal enzyme required to hydrolyze the N-acyl linkage between the fatty acid and sphingosine moieties in ceramide. A deficiency of acid ceramidase activity results in the lipid storage disorder, Farber disease. This study reports a new assay method to detect acid ceramidase activity in vitro using Bodipy or lissamine rhodamine-conjugated ceramide (C12 ceramide; dodecanoylsphingosine). Using mouse kidney extracts as the source of acid ceramidase activity, this new method was compared with an assay using radioactive C12 ceramide (N-[14C]-dodecanoylsphingosine) as a substrate. The Bodipy C12 ceramide substrate provided data very similar to those of the radioactive substrate, but under the experimental conditions tested, it was significantly more sensitive. Using Bodipy C12 ceramide, femtomole quantities of the product, Bodipy dodecanoic acid, could be detected, providing an accurate measure of acid ceramidase activity as low as 0.1 pmol/mg protein/h. Acid ceramidase activities in skin fibroblasts and EBV-transformed lymphoblasts from Farber disease patients were around 7.8 and 10% of those in normal cells, respectively, confirming the specificity of this new assay method. Based on these results, we suggest that this fluorescence-based, high-performance liquid chromatographic technique is a reliable, rapid, and highly sensitive method to determine acid ceramidase activity, and that it could be useful wherever the in vitro detection of acid ceramidase activity is of importance.
ISSN:0003-2697
1096-0309
DOI:10.1006/abio.1999.4284