Identification of the phosphate-translocator from maize mesophyll chloroplasts

Intact maize mesophyll chloroplasts have been isolated in yields of up to 10 mg of chlorophyll per preparation. The chloroplasts were able to reduce 3-phosphoglycerate at a rate of 2.4 mumol of oxygen/min/mg of chlorophyll. This activity was inhibited by preincubating the intact chloroplasts with pyridoxal 5-phosphate. Chloroplast envelopes have been prepared and the protein profile has been obtained on SDS-polyacrylamide gels. The phosphate-translocator from the chloroplast envelope has been identified as a 30kDa polypeptide.