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Radiation inactivation analysis of H + ‐pyrophosphatase from submitochondrial particles of etiolated mung bean seedlings
Author(s) -
Jiang Shih Sheng,
Yang Su Jing,
Kuo Soong Yu,
Pan Rong Long
Publication year - 2000
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(00)01215-1
Subject(s) - submitochondrial particle , pyrophosphatase , inorganic pyrophosphatase , chemistry , etiolation , proton , biochemistry , pyrophosphate , hydrolysis , radiochemistry , enzyme , physics , quantum mechanics
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.