Glycosylation degree of mutant PPT1 molecules. (A) 10 μg of total protein from the cell lysates of transfected COS-1 cells and SFV infected neurons was analyzed by immunoblotting and densitometric scanning. The numbers 3, 2 and 1 indicate the three differently glycosylated forms of PPT1. (B) The graph represents relative amounts of tri-, di-, and monoglycosylated forms of PPT1 in transfected COS-1 cells. The data shown represents an average of three independent experiments and the error bars show the standard deviations between these experiments.