NADH oxidase activity of rat liver plasma membrane activated by guanine nucleotides

• Published in: Biochemical journal Vol. 292; no. 3; pp. 647 - 653
• Main Authors: MORRE, D. J, DAVIDSON, M, GEILEN, C, LAWRENCE, J, FLESHER, G, CROWE, R, CRANE, F. L
• Format: Journal Article
• Language: English
• Published: Colchester Portland Press 15-06-1993
• Subjects: Analytical, structural and metabolic biochemistry; Animals; Biological and medical sciences; Cell Membrane - enzymology; Chlorides; Enzyme Activation; Enzymes and enzyme inhibitors; Fundamental and applied biological sciences. Psychology; Golgi Apparatus - enzymology; Guanine Nucleotides - pharmacology; Guanosine 5'-O-(3-Thiotriphosphate) - pharmacology; Guanosine Diphosphate - analogs & derivatives; Guanosine Diphosphate - pharmacology; Guanosine Triphosphate - pharmacology; Kinetics; Liver - enzymology; Magnesium Chloride - pharmacology; Manganese - pharmacology; Manganese Compounds; Multienzyme Complexes - metabolism; NADH, NADPH Oxidoreductases - metabolism; Oxidoreductases; Rats; Thionucleotides - pharmacology; GTP; Calcium; Rat; Enzyme; Liver; Rodentia; Guanine nucleotide; Adenylate cyclase; Binding protein; Vertebrata; Mammalia; Enzymatic activity; Plasma membrane; Oxidation; Divalent cation; G protein
• ISSN: 0264-6021; 1470-8728
• DOI: 10.1042/bj2920647

The activity of a hormone- and growth-factor-stimulated NADH oxidase of the rat liver plasma membrane responds to guanine nucleotides, but in a manner that differs from that of the classic trimeric and low-molecular-mass monomeric G-proteins. In the absence of added bivalent ions, both GTP and GDP as well as guanosine 5'-[gamma-thio]triphosphate (GTP[gamma-S]) but not guanosine 5'[beta-thio]diphosphate (GDP[beta-S]) stimulate the activity over the range 1 microM to 100 microM. Other di- and tri-nucleotides also stimulate, but only at concentrations of 100 microM or higher. Added bivalent ions are not required either for NADH oxidation or guanine nucleotide stimulation. Bivalent ions (Mg2+ > Mn2+ > or = Ca2+) alone stimulate only slightly at low concentrations and then inhibit at high concentrations. The inhibitions are augmented by GDP or GTP [gamma-S] but not by GTP. Although the activity is the same, or less, in the presence of 0.5 mM MgCl2, GTP at 1-100 nM and other nucleotides at 0.1 mM or 1 mM still stimulate in its presence. The NADH oxidase is activated by mastoparan but aluminum fluoride is weakly inhibitory. Cholera and pertussis toxins elicit only marginal responses. Both the Mg2+ and the GDP and GTP[gamma-S] inhibitions (but not the GTP stimulations) shift to higher concentrations when the membrane preparations are first solubilized with Triton X-100. The results suggest a role for guanine nucleotides in the regulation of plasma membrane NADH oxidase, but with properties that differ from those of either trimeric or the low-molecular-mass G proteins thus far described.