Acyl Carrier Protein

A pantothenate-requiring auxotroph and a β-alanine-requiring auxotroph of Escherichia coli were grown in media supplemented with radioactive pantothenate or β-alanine, respectively. Analyses of extracts of these organisms showed that acyl carrier protein accounts for approximately 90% of the radioactivity associated with the protein fraction. Studies with the pantothenate auxotroph indicate that under the conditions of these experiments acyl carrier protein and coenzyme A are the major cellular constituents which contain pantothenate. In addition, it was found that the cellular concentration of coenzyme A is directly related to the concentration of pantothenate in the medium, whereas the concentration of acyl carrier protein does not vary under a variety of growth conditions.