Chloroplast phosphoproteins: Distribution of phosphoproteins within spinach chloroplasts

Abstract

The distribution of phosphoproteins within spinach chloroplasts was studied. Intact chloroplasts with good rates of CO₂-dependent oxygen evolution were fed [γ-³²P]ATP and then separated into stroma and membrane fractions. Only one major labelled stroma protein was identified by gel electrophoresis/autoradiography, with a mol. wt. of 66 000. The membranes were separated into envelopes and thylakoid fractions. Three labelled proteins were separated by gel electrophoresis in the envelope with mol. wt. of 50 500, 29 000 and 13 000.