Permeability of Isolated Infected Cells from Soybean Nodules

Infected cells from the central zone of mature soybean noduleswere isolated by incubating nodule slices with hydrolytic enzymes,and their permeability to various organic compounds measured.The cells were effectively impermeable to sucrose, fructoseand glucose, readily permeable to malate and succinate and partiallypermeable to glutamate and glutamine. Malate uptake showed saturationkinetics and was competitively inhibited by succinate. Malateuptake was also inhibited by a protonophore and the respiratorypoison antimycin, as well as by butylmalonate, cyanocinnamicacid and other substrate analogues, but not by phthalonate.We conclude that there is a dicarboxylate carrier on the plasmamembraneof soybean infected cells, which catalyses the uptake of malateand which depends on mitochondrial ATP for maximum rates.