Ceramidase catalyzes the hydrolysis of the N-acyl linkage between the fatty acid and sphingosine base in ceramide to produce sphingosine and a free fatty acid. Three isoforms of ceramidases (acid, neutral, and alkaline) have been characterized based on differences in their catalytic pH optimum. C-12 NBD ceramide is a long-chain fluorescent ceramide analog that can be used for the measurement of alkaline and neutral ceramidase activity. It is hydrolyzed efficiently by alkaline ceramidase from P. aeruginosa and by neutral ceramidase from mouse liver. In addition, alkaline and neutral ceramidases from a variety of mammalian cell lines also hydrolyze C-12 NBD ceramide. Acid ceramidase does not appear to utilize C-12 NBD ceramide as a substrate. The possibility exists for C-12 NBD ceramide to also be applied to the measurement of ceramide kinase and/or sphingomyelin synthase activity.
![N-[12-[(7-NITRO-2-1,3-BENZOXADIAZOL-4-YL)AMINO]DODECANOYL]-CERAMIDE](https://www.chemicalbook.com/StructureFile/ChemBookStructure5/GIF/CB4309134.gif)