Functional size of the thylakoid phosphatases determined by radiation inactivation.
Radiation inactivation technique was employed to determine the functional size of phosphatases from thylakoid membrane. The enzymatic activities of phosphatases decayed in a simple function with the increase of radiation dosage. D37 values of 18.8 +/- 2.4-14.1 +/- 1.5 Mrad were obtained, using phosphoserine, phosphothreonine, p-nitrophenol phosphate, and phospho-histone V-S, respectively, as substrates. The molecular masses of 48.2 +/- 6.3-61 +/- 5.7 kDa were yielded by target theory analysis. We thus speculate that the thylakoid alkaline phosphatase is probably a monomer while acid phosphatase is functionally a dimer in situ.
Hsu
L H
LH
Institute of Radiation Biology, College of Nuclear Science, National Tsing Hua University, Hsin Chu, Taiwan, Republic of China.
Tzeng
C M
CM
Pan
R L
RL
D000135:Acid Phosphatase / Q000037:antagonists & inhibitors / Q000737:chemistry* / Q000528:radiation effects; D000469:Alkaline Phosphatase / Q000037:antagonists & inhibitors / Q000737:chemistry* / Q000528:radiation effects; D007425:Intracellular Membranes / Q000201:enzymology; D010944:Plants / Q000201:enzymology*
D000469:Alkaline Phosphatase; D000135:Acid Phosphatase