Comparison of the ability of phospholipids from rat liver lysosomes to reconstitute glucocerebrosidase.
The in situ lipid activator of rat liver glucocerebrosidase was investigated. Rat liver lysosomes were purified (42.9-fold relative to the crude homogenate) by sequential isopycnic centrifugation in sucrose and metrizamide gradients. Lipids were extracted with chloroform:methanol (2:1) and phospholipids were separated by one-dimensional thin-layer chromatography. The phospholipid content of the lysosome preparation was 0.28 mumol lipid phosphorus/mg protein. Phosphatidylcholine was present as the major nonacidic phospholipid (39.3%). Of the acidic phospholipids, phosphatidylinositol and phosphatidylserine were present in the greatest amounts (12.0 and 19.7%, respectively). The resolved phospholipids were tested separately and in the presence of a heat-stable factor from Gaucher spleen for their ability to reconstitute butanol-delipidated rat liver glucocerebrosidase activity. Alone or in the presence of the heat-stable factor, phosphatidylserine and phosphatidylinositol were the most effective activators of glucocerebrosidase. Bis(monoacylglyceryl) phosphate derived from rat liver tritosomes or rabbit lung macrophages was also effective in reconstituting beta-glucosidase activity.
D000818:Animals; D002499:Centrifugation, Density Gradient; D004789:Enzyme Activation; D005959:Glucosidases / Q000378:metabolism*; D005962:Glucosylceramidase / Q000378:metabolism*; D066298:In Vitro Techniques; D008099:Liver / Q000201:enzymology*; D008246:Lysophospholipids; D008247:Lysosomes / Q000201:enzymology*; D008297:Male; D050178:Monoglycerides; D010712:Phosphatidic Acids / Q000302:isolation & purification; D010743:Phospholipids / Q000302:isolation & purification / Q000502:physiology*; D051381:Rats; D011919:Rats, Inbred Strains
D008246:Lysophospholipids; D050178:Monoglycerides; D010712:Phosphatidic Acids; D010743:Phospholipids; C012786:bis(monoacylglyceryl)phosphate; D005959:Glucosidases; D005962:Glucosylceramidase