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Characterization of ferric reducing activity in roots of Fe‐deficient Phaseolus vulgaris
Author(s) -
Bienfait H. F.,
Bino R. J.,
Bliek A. M.,
Duivenvoorden J. F.,
Fontaine J. M.
Publication year - 1983
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1111/j.1399-3054.1983.tb00757.x
Subject(s) - phaseolus , arrhenius plot , ferric , substrate (aquarium) , chemistry , enzyme , metabolite , enzyme assay , ferric iron , kinetics , nuclear chemistry , horticulture , botany , biochemistry , activation energy , biology , inorganic chemistry , organic chemistry , ecology , physics , quantum mechanics , ferrous
Iron‐deficient bean plants ( Phaseolus vulgaris L. cv. Prélude) exhibited a ferric reducing activity in the roots, with kinetics characteristic for matrix‐bound enzymes: the reaction rate was proportional to substrate (Fe‐EDTA) concentration until 100 μ M , and at higher concentrations it leveled off to a maximum; the Lineweaver‐Burk plot yielded a non‐linear relationship between rate −1 and substrate −1 . The Arrhenius plot yielded apparent activation energies which were dependent on substrate concentration. No evidence was obtained for the secretion by roots of a low molecular weight metabolite involved in the reduction of iron prior to its uptake. The results are interpreted to indicate that the ferric reducing activity in the roots of iron‐deficient bean plants is located in an enzyme in the plasmalemma of the cortex or epidermis cells.