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- Title
Activities of Cu-containing proteins in Cu-depleted pea leaves.
- Authors
Ayala, Matilde Barón; Sandmann, Gerhard
- Abstract
The effect of Cu deficiency on Cu-containing enzymes and on their activities was studied with two subsequent generations of Cu-deficient pea plants (Pisum sativum L., cv. Progress) grown in low Cu2+ media. Cu deficiency caused growth inhibition and a decrease in photosynthesis as well as in the activities of 3 Cu-containing enzymes: diamine oxidase (EC 1.4.3.6), ascorbate oxidase (EC 1.10.3.3) and superoxide dismutase (EC 1.15.1.1). Determinations of photosynthetic electron-transport rates as well as the concentrations of several redox components showed that the target of Cu deprivation in the photosynthetic apparatus is the synthesis of Cu-containing plastocyanin which is positively correlated to the Cu content of the leaves. Inhibited formation of plastocyanin resulted in low activities of photosynthetic electron transport in photosystem I. Under Cu-deficient conditions, the activities of diamine oxidase and ascorbate oxidase were inhibited by about 50% in the first and 80% in the second generation of pea plants. Enzyme assays showed an inhibition of the activities of both the plastidic and cytoplasmic Cu/Zn-containing superoxide dismutases. An observed simultaneous increase of Mn-superoxide dismutase may be a compensation mechanism to partially maintain the total superoxide-dismutase activity under Cu-deficient conditions. This result indicates that the formation of superoxide-dismutase isoenzymes is interdependent and coordinated.
- Subjects
PEA diseases &; pests; HYPOCUPREMIA; DEFICIENCY diseases; EFFECT of minerals on plants; PHYSIOLOGICAL effects of copper; PLASTOCYANIN; PLANT proteins; SUPEROXIDE dismutase; PLANTS
- Publication
Physiologia Plantarum, 1988, Vol 72, Issue 4, p801
- ISSN
0031-9317
- Publication type
Article
- DOI
10.1111/j.1399-3054.1988.tb06382.x