5'-Nucleotidase in rat liver lysosomal membranes is anchored via glycosyl-phosphatidylinositol.
We have previously demonstrated that 5'-nucleotidase, known as a plasma membrane enzyme, is also distributed both in rat liver tritosomal membranes and contents (J. Biochem. 101, 1077-1085, 1987). When the lysosomal membranes isolated from rat livers were incubated with phosphatidylinositol-specific phospholipase C purified from B. thuringiensis, about 70% of 5'-nucleotidase activity was released from the membranes. Judging from the result by phase separation with Triton X-114, the enzyme solubilized by the phospholipase C digestion showed a hydrophilic nature such as that of the tritosomal contents. Immunoblot analysis showed that the molecular weight of 5'-nucleotidase released from the lysosomal membranes by the phospholipase C digestion was almost identical with that of the enzymes from the Tritosomal contents. The above results showed that the phosphatidylinositol-specific phospholipase C-like enzyme in the lysosomes may be responsible for the conversion of the lysosomal membrane-bound 5'-nucleotidase to the soluble form present in the lysosomal matrix.
Tanaka
Y
Y
Faculty of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan.
Himeno
M
M
Taguchi
R
R
Ikezawa
H
H
Kato
K
K
D015720:5'-Nucleotidase / Q000378:metabolism*; D000818:Animals; D006017:Glycolipids / Q000378:metabolism*; D017261:Glycosylphosphatidylinositols; D015151:Immunoblotting; D008099:Liver / Q000201:enzymology*; D008247:Lysosomes / Q000201:enzymology*; D008297:Male; D008565:Membrane Proteins / Q000378:metabolism; D010716:Phosphatidylinositols / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D010738:Type C Phospholipases / Q000378:metabolism
D006017:Glycolipids; D017261:Glycosylphosphatidylinositols; D008565:Membrane Proteins; D010716:Phosphatidylinositols; D015720:5'-Nucleotidase; D010738:Type C Phospholipases