INTRACELLULAR-LOCALIZATION OF CA1P AND CA1P PHOSPHATASE-ACTIVITY IN LEAVES OF PHASEOLUS-VULGARIS L

CA1P and CA1P phosphatase occur in the chloroplasts of leaf mesophyll cells of many species. However, whether either may occur exclusively i n the chloroplast has not yet been established. To examine their intra cellular distribution, mature, dark- or light-treated leaves of Phaseo lus vulgaris were frozen, lyophilized and then centrifuged in density gradients of heptane and tetrachloroethylene. After gradient fractiona tion, both CA1P and CA1P phosphatase activity co-segregated with chlor oplast material. Distribution analyses using sub-cellular compartment markers indicated that both CA1P and CA1P phosphatase do occur exclusi vely in leaf chloroplasts.