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 in the chloroplast has not yet been established. To examine their intracellular distribution, mature, dark-or light-treated leaves of Phaseolus vulgaris were frozen, lyophilized and then centrifuged in density gradients of heptane and tetrachloroethylene. After gradient fractionation, both CA1P and CA1P phosphatase activity co-segregated with chloroplast material. Distribution analyses using sub-cellular compartment markers indicated that both CA1P and CA1P phosphatase do occur exclusively in leaf chloroplasts.