Effect of Ca²⁺ and CaM on activities of Ca²⁺-ATPase, SOD and PEA in apple fruits

The relationship between Ca2+ ATPase and Ca2+ transport in plasma membrane vesicles isolated from pulp cell of apple fruits (malus pumila) were probed by using 45Ca2+ trace technology etc, and effect of selected inhibitors and stimuli of Ca2+ and CaM on Ca2+-ATPase, SOD and PEA activities were investigated in solution culture experiment using flesh discs of apple. Results showed that the Ca2+-ATPase is stimulated by the Ca2+ ionophore A23187 and is localized at the plasma membrane. Ca2+-ATPase activity and Ca2+ uptake present very similar saturation kinetics with erythrosin B,demonstrating that it is this enzyme that drive Ca2+ transport in plasma membrane vesicles. Ca2+-ATPase activity were markedly influenced by both Ca2+ and CaM, while both SOD and PEA activities were regulated only by Ca2+, but none by CaM.