title: Functional size of the thylakoid phosphatases determined by radiation inactivation.
abstract: 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.
authors.affiliation: Institute of Radiation Biology, College of Nuclear Science, National Tsing Hua University, Hsin Chu, Taiwan, Republic of China.
authors.forename: L H
authors.initials: LH
authors.lastname: Hsu
authors.forename: C M
authors.initials: CM
authors.lastname: Tzeng
authors.forename: R L
authors.initials: RL
authors.lastname: Pan
mesh_terms: 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*
chemical_list: D000469:Alkaline Phosphatase; D000135:Acid Phosphatase