title: Phospholipase D activity of rat brain neuronal nuclei.
abstract: Phospholipase D activity of rat brain neuronal nuclei, measured with exogenous phosphatidylcholine as substrate, was characterized. The measured activity of neuronal nuclei was at least 36-fold greater than the activity in glia nuclei. The pH optimum was 6.5, and unsaturated but not saturated fatty acids stimulated the enzyme. The optimal concentration of sodium oleate for stimulation of the enzyme activity was 1.2 mM in the presence of 0.75 mM phosphatidylcholine. This phospholipase D activity was cation independent. In the absence of NaF, used as a phosphatidic acid phosphatase inhibitor, the principal product was diglyceride; whereas in the presence of NaF, the principal product was phosphatidic acid. The phospholipase D, in addition to having hydrolytic activity, was able to catalyze a transphosphatidylation reaction. Maximum phosphatidylethanol formation was seen with 0.2-0.3 M ethanol. GTPgammaS, ATPgammaS, BeF2, AIF3, phosphatidic acid, and phosphatidylethanol inhibited the neuronal nuclei phospholipase D activity. The addition of the cytosolic fraction of brain, liver, kidney, spleen, and heart to the incubation mixtures resulted in inhibition of the phospholipase D activity. Phospholipase D activity was detectable in nuclei prepared from rat kidney, spleen, heart, and liver.
authors.affiliation: Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of Manitoba, Winnipeg, Canada.
authors.forename: J N
authors.initials: JN
authors.lastname: Kanfer
authors.forename: D
authors.initials: D
authors.lastname: McCartney
authors.forename: I N
authors.initials: IN
authors.lastname: Singh
authors.forename: L
authors.initials: L
authors.lastname: Freysz
mesh_terms: D000255:Adenosine Triphosphate / Q000031:analogs & derivatives / Q000378:metabolism; D000818:Animals; D002118:Calcium / Q000378:metabolism; D002467:Cell Nucleus / Q000201:enzymology; D002540:Cerebral Cortex / Q000201:enzymology / Q000648:ultrastructure; D003600:Cytosol / Q000201:enzymology; D016244:Guanosine 5'-O-(3-Thiotriphosphate) / Q000378:metabolism; D007668:Kidney / Q000201:enzymology; D008099:Liver / Q000201:enzymology; D009206:Myocardium / Q000201:enzymology; D009355:Neomycin / Q000494:pharmacology; D009457:Neuroglia / Q000201:enzymology; D009474:Neurons / Q000201:enzymology*; D019301:Oleic Acid; D009829:Oleic Acids / Q000378:metabolism; D010713:Phosphatidylcholines / Q000378:metabolism; D019269:Phosphatidylinositol 4,5-Diphosphate; D018129:Phosphatidylinositol Phosphates / Q000378:metabolism; D010739:Phospholipase D / Q000037:antagonists & inhibitors / Q000378:metabolism*; D051381:Rats; D012969:Sodium Fluoride / Q000494:pharmacology; D013154:Spleen / Q000201:enzymology
chemical_list: D009829:Oleic Acids; D010713:Phosphatidylcholines; D019269:Phosphatidylinositol 4,5-Diphosphate; D018129:Phosphatidylinositol Phosphates; D019301:Oleic Acid; C022571:adenosine 5'-O-(3-thiotriphosphate); D016244:Guanosine 5'-O-(3-Thiotriphosphate); D000255:Adenosine Triphosphate; D012969:Sodium Fluoride; D010739:Phospholipase D; D009355:Neomycin; D002118:Calcium