Synthesis of nitrogenase by isolated heterocysts

Heterocysts isolated from Anabaena variabilis incorporate ¹⁴C]leucine and ³⁵S]methionine into trichloroacetic acid-precipitable material in the light. Analysis by polyacrylamide gel electrophoresis shows that the radioactivity is present in polypeptides of discrete sizes. However, the relative proportions of different proteins synthesized by isolated heterocysts differ from the relative proportions of those proteins incorporated by the heterocysts in intact filaments. The two components of nitrogenase are among the proteins synthesized by the isolated heterocysts.