Latency of some glycosidases of rat liver lysosomes.
The latency of the alpha-glucosidase activity of intact rat liver lysosomes was studied by using four substrates (glycogen, maltose, p-nitrophenyl, alpha-glucoside, alpha-fluoroglucoside) at a range of substrate concentrations. The results indicate that the entire lysosome population is impermeable to glycogen and maltose, but a proportion of lysosomes are permeable to alpha-fluoroglucoside and a still higher proportion permeable to p-nitrophenyl alpha-glucoside. Incubation at 37 degrees C in an osmotically protected buffer of of pH 5.0 caused lysosomes to become permeable to previously impermeant substrates and ultimately to release their alpha-glucosidase into the medium. The latencies of lysosomal beta-glucosidase and beta-galactosidase were examined by using p-nitrophenyl beta-glucoside and beta-galactoside as substrates. The results indicate permeability properties to these substrates similar to that to p-nitrophenyl alpha-glucoside. On incubation in an osmotically protected buffer of pH 5, lysosomes progressively released their beta-galactosidase in soluble form, but beta-glucosidase remained attached to sedimentable material. Lysosomal beta-glucosidase was inhibited by 0.1% Triton X-100; alpha-glucosidase and beta-galactosidase were not inhibited.
D000818:Animals; D002463:Cell Membrane Permeability; D005696:Galactosidases / Q000378:metabolism; D005959:Glucosidases / Q000378:metabolism; D005960:Glucosides / Q000378:metabolism; D006003:Glycogen / Q000378:metabolism; D006026:Glycoside Hydrolases / Q000378:metabolism*; D007700:Kinetics; D008099:Liver / Q000201:enzymology; D008247:Lysosomes / Q000201:enzymology*; D008297:Male; D008320:Maltose / Q000378:metabolism; D051381:Rats
D005960:Glucosides; D008320:Maltose; D006003:Glycogen; D005696:Galactosidases; D005959:Glucosidases; D006026:Glycoside Hydrolases