Involvement of 70S ribosomes in the synthesis of some polypeptides constitutive of inner and outer envelope membranes of spinach chloroplast

Proteosynthesis was performed in organello, using intact chloroplasts isolated from spinach (Spinacia oleracea L.) leaves to determine the extent of the plastid genome and 70S ribosomes involvement in the synthesis of chloroplast envelope proteins. The chloroplasts were ruptured in a hypertonic medium and the four fractions (thylakoids, stroma, inner and outer envelope membranes) purified. The proteins associated with each fraction were separated by temperature-induced phase partition in the presence of Triton X-114 according to their hydrophobic or hydrophilic characteristic. The products of protein synthesis were analysed by one and two dimensional electrophoresis as well as by autoradiography and immunology