Sulfur metabolism in Escherichia coli. IV. Influence of nonmethionine sulfur compounds upon a methionine requiring mutant.

The inability of the methionine requiring Escherichia coli mutant (1-344) to grow in methionine free media containing inorganic sulfur, cystine, or homocystine has been demonstrated (Lampen et al., 1947). While methionine has been shown to be essential for growth, the metabolism of nonmethionine sulfur added to media containing methionine has not been investigated directly. In the results reported here we have attempted to observe some of the metabolic reactions occurring on either side of the biochemical block, and to determine what degree of coupling exists between the necessary utilization of methionine and the metabolism of inorganic sulfur.