CONTROL BY ENDOGENOUSLY SYNTHESIZED ARGININE OF THE FORMATION OF ORNITHINE TRANSCARBAMYLASE IN ESCHERICHIA COLI

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Abstract
The control of ornithine transcarbamylase synthesis in Escherichia coli by endogenously produced arginine has been analyzed in bradythrophs (partially blocked mutants) and in a wild[long dash]type strain grown in an enriched but arginine -free medium. In arginine bradytrophs, in which the growth rate is limited by the rate of arginine formation, ornithine transcarbamylase is formed 25 times faster than in the wild-type in which the growth rate is not limited by the rate of arginine formation. In the wild-type a limitation in the supply of endogenously formed arginine can be achieved by growth in the arginine-free medium. Under these conditions ornithine transcarbamylase is formed 6 times faster than during growth in minimal medium. These results lend further support to the previously proposed hypothesis that the intracellular level of arginine regulates the rate of formation of enzymes involved in its own biosynthesis.