Phosphate modification of fructose-1,6-bisphosphate aldolase in Escherichia coli

When E. coli carrying multicopy plasmids for fructose-1,6-P2 aldolase or phosphoglycerate kinase was grown in the presence of 32Pi, there was label at the position of cognate high level polypeptide after SDS-PAGE. As tested for aldolase, the label was resistant to acetone, RNase, and hot TCA treatments, and was also observed by immunoprecipitation, which was competed for by purified aldolase. Incorporation of label also occurred in the presence of chloramphenicol. Immunoprecipitation revealed apparent aldolase labeling in the wild type strain as well.