Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. Alkaline ceramidase 1 also known as ACER1 is a ceramidase enzyme which in humans is encoded by the ACER1 gene.ACER1 mediates cellular differentiation by controlling the generation of sphingosine (SPH) and sphingosine-1-phosphate (S1P).ACER1 mediates cellular differentiation by controlling the generation of sphingosine (SPH) and sphingosine-1-phosphate (S1P).