Ceramidase (EC 220.127.116.11, acylsphingosine deacylase, glycosphingolipid ceramide deacylase) is an enzyme which cleaves fatty acids from ceramide, producing sphingosine (SPH) which in turn is phosphorylated by a sphingosine kinase to form sphingosine-1-phosphate (S1P).
Ceramide, SPH, and S1P are bioactive lipids that mediate cell proliferation, differentiation, apoptosis, adhesion, and migration. Presently, 7 human ceramidases encoded by 7 distinct genes have been cloned:
- acid ceramidase (ASAH1) – cell survival
- neutral ceramidase (ASAH2, ASAH2B, ASAH2C) – protective against inflammatory cytokines
- alkaline ceramidase 1 (ACER1) – mediating cell differentiation by controlling the generation of SPH and S1P
- alkaline ceramidase 2 (ACER2) – important for cell proliferation and survival
- alkaline ceramidase 3 (ACER3)
A deficiency in ASAH1 is associated with Farber disease.