Comparisons of Plasma Membranes from Shoots and Roots of Winter Rye (Secale cerealeL. cv. Puma): Polypeptide Composition, ATPase Activity and Specific Naphthylphthalamic Acid Binding Capacity1

摘要

Polypeptide compositions, ATPase characteristics, and theN-1-naphthylphthalamic acid binding capacity of plasma membranes prepared from winter rye (Secale cerealeL. cv. Puma) shoots and roots were examined and compared.Some unique polypeptides were revealed in each plasma membrane by one- and two-dimensional slab gel electrophoresis. A difference was also detected in glycopeptide compositions. The plasma membranes from both organs contained Mg2+-stimulated ATPase exhibiting slightly different properties in the divalent cation specificity and the kinetic constants. The ATPase activities from both organs showed a similar optimum pH around 6.5, simple Michaelis-Menten saturation with increasing ATP-Mg concentrations, and little K+-stimulation at the optimum pH. Both ATPases were inhibited by orthovanadate, however, the degree of inhibition was a little different in each membrane sample. The specificN-1-naphthylphthalamic acid binding capacity in the shoot plasma membrane was 2.6-fold higher than that in the root plasma membrane.These results suggest that polypeptide compositions of plasma membranes vary corresponding with a difference in the physiological functions of plasma membranes between shoots and roots of winter rye.