Sap-C is assumed to represent Saposin-C, which " stimulates the hydrolysis of glucosylceramide by beta-glucosylceramidase (EC 3.2.1.45) and galactosylceramide by beta-galactosylceramidase (EC 3.2.1.46). Saposin-C apparently acts by combining with the enzyme and acidic lipid to form an activated complex, rather than by solubilizing the substrate." Source:[https://www.uniprot.org/uniprotkb/P07602/entry]