title: Localization of oxidized nocotinamide--adenine dinucleotide glycohydrolase in the mouse liver nuclear envelope.
abstract: NAD+ glycohydrolase activity located in the nuclear envelope was maximally solubilized by treatment with 0.1--0.2% Triton X-100. The residual activity largely represents the chromatin-associated NAD+ glycohydrolase. Under these conditions the phospholipids were extensively solubilized (over 90%) while leaving the nuclei physically stable, although the nuclear membranes were removed, as shown by electron microscopy. After Triton X-100 treatment, deoxyribonuclease I did not significantly affect the residual NAD+ glycohydrolase activity, although the DNA was completely broken down. This enzyme activity can be released from the nuclear pellet by incubation with phospholipase C. For comparative studies, the glucose 6-phosphatase activity, known to be present in the nuclear envelope, was investigated. Treatment with 0.01% Triton X-100 released 10--20% of the phospholipids, but without solubilizing either glucose 6-phosphatase or NAD+ glycohydrolase. Higher Triton X-100 concentrations (0.1--1.0%) inhibited glucose 6-phosphatase, but not NAD+ glycohydrolase activity. NAD+ glycohydrolase is apparently present in a latent form in the nuclear envelope. Glucose 6-phosphatase, However, shows no such latency.
mesh_terms: D000818:Animals; D002843:Chromatin / Q000201:enzymology; D003851:Deoxyribonucleases / Q000494:pharmacology; D005952:Glucose-6-Phosphatase / Q000378:metabolism; D066298:In Vitro Techniques; D008099:Liver / Q000201:enzymology* / Q000648:ultrastructure; D008297:Male; D051379:Mice; D008854:Microscopy, Electron; D009244:NAD+ Nucleosidase / Q000378:metabolism*; D009685:Nuclear Envelope / Q000187:drug effects / Q000201:enzymology / Q000648:ultrastructure; D010740:Phospholipases / Q000494:pharmacology; D010743:Phospholipids / Q000378:metabolism; D011092:Polyethylene Glycols / Q000494:pharmacology
chemical_list: D002843:Chromatin; D010743:Phospholipids; D011092:Polyethylene Glycols; D003851:Deoxyribonucleases; D010740:Phospholipases; D005952:Glucose-6-Phosphatase; D009244:NAD+ Nucleosidase