title: Radiation inactivation analysis of H(+)-pyrophosphatase from submitochondrial particles of etiolated mung bean seedlings.
abstract: Radiation inactivation analysis was employed to determine the functional masses of enzymatic activity and proton translocation of H(+)-pyrophosphatase from submitochondrial particles of etiolated mung bean seedlings. The activities of H(+)-pyrophosphatase decayed as a simple exponential function with respect to radiation dosage. D(37) values of 6.9+/-0.3 and 7.5+/-0.5 Mrad were obtained for pyrophosphate hydrolysis and its associated proton translocation, yielding molecular masses of 170+/-7 and 156+/-11 kDa, respectively. In the presence of valinomycin and 50 mM KCl, the functional size of H(+)-pyrophosphatase of tonoplast was decreased, while that of submitochondrial particles remained the same, indicating that they are two distinct types of proton pump using PP(i) as their energy source.
authors.affiliation: Department of Life Science, College of Life Science, National Tsing Hua University, Hsin Chu, Taiwan.
authors.forename: S S
authors.initials: SS
authors.lastname: Jiang
authors.forename: S J
authors.initials: SJ
authors.lastname: Yang
authors.forename: S Y
authors.initials: SY
authors.lastname: Kuo
authors.forename: R L
authors.initials: RL
authors.lastname: Pan
mesh_terms: D000595:Amino Acid Sequence; D002458:Cell Fractionation; D003037:Cobalt Radioisotopes; D003624:Darkness; D004307:Dose-Response Relationship, Radiation; D004591:Electrophoresis, Polyacrylamide Gel; D007887:Fabaceae / Q000201:enzymology* / Q000254:growth & development; D015151:Immunoblotting; D043564:Inorganic Pyrophosphatase; D010446:Peptide Fragments / Q000737:chemistry; D010946:Plants, Medicinal; D011755:Pyrophosphatases / Q000037:antagonists & inhibitors / Q000302:isolation & purification / Q000528:radiation effects*; D011839:Radiation, Ionizing; D013367:Submitochondrial Particles / Q000201:enzymology*
chemical_list: D003037:Cobalt Radioisotopes; D010446:Peptide Fragments; D011755:Pyrophosphatases; D043564:Inorganic Pyrophosphatase