Heat activation of the Fe protein of nitrogenase from Rhodospirillum rubrum.

Abstract

The Fe protein of nitrogenase from Rhodospirillum rubrum isolated in the inactive form was found to be activated in vitro by heating. This heat activation was dependent upon temperature, pH, and enzyme concentration. During activation by heating, a change in the subunit composition of Fe protein was observed on sodium dodecyl sulfate gels. The upper subunit decreases and the lower subunit increased. All components of the modifying group on inactive Fe protein appear to be lost upon heat activation.