Characterization and partial purification of multiple electron transport activities in plasma membranes from maize (Zea mays) roots |
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Authors: | Douglas G. Luster Thomas J. Buckhout |
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Affiliation: | Plant Photobiology Lab., Bldg. 046A. U.S. Dept of Agriculture –Agricultural Research Service. Beltsville Agricultural Research Center, Beltsville, MD 20705, USA |
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Abstract: | The plasma membrane of eukaryotic cells contains endogenous, integral electron transport proteins. In the maize ( Zea mays L. cv. Golden Cross Bantam) root plasma membrane, these activities include NAD(P)H-ferricyanide reductase. NAD(P)H-duroquinone reductase (1.6.5.1) and NAD(P)H-ascorbate free-radical reductase (EC 1.6.5.4). Differences in degree of stimulation upon vesicle rupture with detergent and in specificities for pyridine nucleotides suggest that these activities constitute distinct components in the membranes. Solubilization of reductase activities was examined using Triton X-100 over a wide range of retergent-to-protein ratios. The Triton-solubilized enzymes were purified using dye-ligand affinity chromatography on Cibacron blue 3G-A agarose utilizing biospecific elution with NADH. Resolution of the redox activities was accomplished upon differential elution with 0.1.1.0 and 10 m M NADH. The distinctive characteristics of the enzymes and the differential chromatographic behavior of the respective activities provided evidence for the presence of separate enzymatic redox components in maize root plasma membranes with implications for an electron transfer chain. |
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Keywords: | Aqueous two-phase partitioning Cibacron blue 3G-A agarose dyeligand affinity chromatography detergent solubilization maize electron transport maize roots NAD(P)H-ascorbate free-radical reductase NAD(P)H-duroquinone reductase NAD(P)H-ferricyanide reductase plasma membrane Zea mays |
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