Fig. 7.

Sap C facilitates the hydrolysis of membrane bound GlcCer by GBA1 even in the absence of anionic phospholipid (BMP). GlcCer hydrolysis is Sap C dose dependent (A) and the Sap C-induced GlcCer hydrolysis by GBA1 is significant even in the absence of BMP, but at higher GBA1 concentration. However, the presence of BMP tremendously enhances the Sap C activity. The pH profile of GlcCer hydrolysis becomes narrower in the presence of both Sap C and anionic lipid, BMP (B). The pH optimum for all experiments remains 4.5 in the presence or absence of Sap C, with the narrowest pH profile obtained during the combined presence of both Sap C and BMP. The experiments were carried out using 400 and 60 ng GBA1 per assay for neutral and anionic liposomes (containing 20 mol% BMP), respectively, at pH 4.5, under 30 min incubation and at 37°C. Mean – SEM (n = 4–6).