PROLINE SYNTHESIS IN ESCHERICHIA-COLI . A PROLINE-INHIBITABLE GLUTAMIC ACID KINASE

The object of this work was the identification of the first enzyme in the biosynthesis of proline in Escherichia coli. A glutamic acid-dependent reaction, which releases Pi from ATP and which is inhibitable by proline, was identified in extracts of these bacteria. The reaction in vitro is dependent upon the presence of imidazole. The reaction was implicated in proline biosynthesis on the basis of its sensitivity to inhibition by proline and because extracts of cells not subject to end-product inhibition in vivo catalyzed a reaction which was not inhibited in vitro. © 1969.